clk: qoriq: avoid format string warning

clang-22 warns about the use of non-variadic format arguments passed into
snprintf():

drivers/clk/clk-qoriq.c:925:39: error: diagnostic behavior may be improved by adding the
      'format(printf, 7, 8)' attribute to the declaration of 'create_mux_common' [-Werror,-Wmissing-format-attribute]
  910 | static struct clk * __init create_mux_common(struct clockgen *cg,
      | __attribute__((format(printf, 7, 8)))
  911 |                                              struct mux_hwclock *hwc,
  912 |                                              const struct clk_ops *ops,
  913 |                                              unsigned long min_rate,
  914 |                                              unsigned long max_rate,
  915 |                                              unsigned long pct80_rate,
  916 |                                              const char *fmt, int idx)
  917 | {
  918 |         struct clk_init_data init = {};
  919 |         struct clk *clk;
  920 |         const struct clockgen_pll_div *div;
  921 |         const char *parent_names[NUM_MUX_PARENTS];
  922 |         char name[32];
  923 |         int i, j;
  924 |
  925 |         snprintf(name, sizeof(name), fmt, idx);
      |                                              ^
drivers/clk/clk-qoriq.c:910:28: note: 'create_mux_common' declared here
  910 | static struct clk * __init create_mux_common(struct clockgen *cg,

Rework this to pass the 'int idx' as a varargs argument, allowing the
format string to be verified at the caller location.

Fixes: 0dfc86b317 ("clk: qoriq: Move chip-specific knowledge into driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk-qoriq.c

@@ -907,13 +907,11 @@ static const struct clockgen_pll_div *get_pll_div(struct clockgen *cg,
 	return &cg->pll[pll].div[div];
 }
 
-static struct clk * __init create_mux_common(struct clockgen *cg,
-					     struct mux_hwclock *hwc,
-					     const struct clk_ops *ops,
-					     unsigned long min_rate,
-					     unsigned long max_rate,
-					     unsigned long pct80_rate,
-					     const char *fmt, int idx)
+static struct clk * __init __printf(7, 8)
+create_mux_common(struct clockgen *cg, struct mux_hwclock *hwc,
+		  const struct clk_ops *ops, unsigned long min_rate,
+		  unsigned long max_rate, unsigned long pct80_rate,
+		  const char *fmt, ...)
 {
 	struct clk_init_data init = {};
 	struct clk *clk;
@@ -921,8 +919,11 @@ static struct clk * __init create_mux_common(struct clockgen *cg,
 	const char *parent_names[NUM_MUX_PARENTS];
 	char name[32];
 	int i, j;
+	va_list args;
 
-	snprintf(name, sizeof(name), fmt, idx);
+	va_start(args, fmt);
+	vsnprintf(name, sizeof(name), fmt, args);
+	va_end(args);
 
 	for (i = 0, j = 0; i < NUM_MUX_PARENTS; i++) {
 		unsigned long rate;