clk: microchip: core: allow driver to be compiled with COMPILE_TEST

This driver currently only supports builds against a PIC32 target. To
avoid future breakage in the future, let's update the Kconfig and the
driver so that it can be built with CONFIG_COMPILE_TEST enabled.

Note that with the existing asm calls is not how I'd want to do this
today if this was a new driver, however I don't have access to this
hardware. To avoid any breakage, let's keep the existing behavior.

Signed-off-by: Brian Masney <bmasney@redhat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

drivers/clk/microchip/Kconfig

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 config COMMON_CLK_PIC32
-	def_bool COMMON_CLK && MACH_PIC32
+	def_bool (COMMON_CLK && MACH_PIC32) || COMPILE_TEST
 
 config MCHP_CLK_MPFS
 	bool "Clk driver for PolarFire SoC"

drivers/clk/microchip/clk-core.c

@@ -75,6 +75,7 @@
 /* SoC specific clock needed during SPLL clock rate switch */
 static struct clk_hw *pic32_sclk_hw;
 
+#ifdef CONFIG_MATCH_PIC32
 /* add instruction pipeline delay while CPU clock is in-transition. */
 #define cpu_nop5()			\
 do {					\
@@ -84,6 +85,9 @@ do {					\
 	__asm__ __volatile__("nop");	\
 	__asm__ __volatile__("nop");	\
 } while (0)
+#else
+#define cpu_nop5()
+#endif
 
 /* Perpheral bus clocks */
 struct pic32_periph_clk {