realtek: Fix missing clock module CONFIG setting

Since introduction of clock driver we have a new kernel config
setting. Provide an initial value for the 930x targets.

Signed-off-by: Markus Stockhausen <[email protected]>

target/linux/realtek/rtl930x/config-5.10

@@ -14,6 +14,7 @@ CONFIG_CLKSRC_MMIO=y
 CONFIG_CLONE_BACKWARDS=y
 CONFIG_COMMON_CLK=y
 CONFIG_COMMON_CLK_BOSTON=y
+# CONFIG_COMMON_CLK_REALTEK is not set
 CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CONSOLE_LOGLEVEL_DEFAULT=15
 CONFIG_CPU_BIG_ENDIAN=y