rockchip: enable SYS_NS16550 for all SoCs by default

All rockchip SoCs can use ns16550 driver, enable it for all
and set SYS_NS16550_MEM32 for all SoCs.

Version-changes: 2
- use imply instead of select

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7212fc5..c930fa2 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1185,6 +1185,7 @@
 	imply TPL_SYSRESET
 	imply ADC
 	imply SARADC_ROCKCHIP
+	imply SYS_NS16550
 
 config TARGET_THUNDERX_88XX
 	bool "Support ThunderX 88xx"