dt-bindings: soc: spacemit: k3: add i2s_sysclk, i2s_bclk_factor and i2s1_sysclk_src IDs

Add three new clock IDs to expose clocks introduced by the topology fix:
- CLK_MPMU_I2S_SYSCLK (51): the common i2s sysclk DDN at MPMU_ISCCR1
- CLK_MPMU_I2S_BCLK_FACTOR (52): the implicit /2 factor feeding i2s_bclk
- CLK_MPMU_I2S1_SYSCLK_SRC (53): the dedicated i2s1 sysclk source mux

CLK_MPMU_I2S1_SYSCLK keeps its existing ID (34) but will be repointed to
the real per-instance i2s1 clock in a subsequent patch. No in-tree user
references this ID so the semantic change is contained.

Fixes: efe897b557 ("dt-bindings: soc: spacemit: k3: add clock support")
Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Reviewed-by: Yixun Lan <dlan@kernel.org>
Link: https://patch.msgid.link/20260717-k3-clk-fix-i2s-v1-1-e95001a692ee@linux.spacemit.com
Signed-off-by: Yixun Lan <dlan@kernel.org>

include/dt-bindings/clock/spacemit,k3-clocks.h

@@ -145,6 +145,9 @@
 #define CLK_MPMU_I2S3_SYSCLK     48
 #define CLK_MPMU_I2S4_SYSCLK     49
 #define CLK_MPMU_I2S5_SYSCLK     50
+#define CLK_MPMU_I2S_SYSCLK      51
+#define CLK_MPMU_I2S_BCLK_FACTOR 52
+#define CLK_MPMU_I2S1_SYSCLK_SRC 53
 
 /* APBC clocks */
 #define CLK_APBC_UART0           0