rockchip: add weak function symbol called at the beginning of misc_init_r

Most Rockchip boards who override misc_init_r do it only to call another
function and keep the rest unchanged. Therefore to allow for less
duplication, let's just add a weak function symbol that is called inside
misc_init_r.

Cc: Quentin Schulz <foss+uboot@0leil.net>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>

arch/arm/mach-rockchip/board.c

@@ -297,6 +297,11 @@ int fastboot_set_reboot_flag(enum fastboot_reboot_reason reason)
 #endif
 
 #ifdef CONFIG_MISC_INIT_R
+__weak int rockchip_early_misc_init_r(void)
+{
+	return 0;
+}
+
 __weak int misc_init_r(void)
 {
 	const u32 cpuid_offset = CFG_CPUID_OFFSET;
@@ -304,6 +309,10 @@ __weak int misc_init_r(void)
 	u8 cpuid[cpuid_length];
 	int ret;
 
+	ret = rockchip_early_misc_init_r();
+	if (ret)
+		return ret;
+
 	ret = rockchip_cpuid_from_efuse(cpuid_offset, cpuid_length, cpuid);
 	if (ret)
 		return ret;