rockchip: Clean up CPU selection

In preparation for RK3368 and RK3399, which need to select ARM64, don't
select CPU_V7 at the ARCH_ROCKCHIP level but at the SoC level instead.

Cc: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arm/Kconfig

@@ -843,7 +843,6 @@ config ARCH_ROCKCHIP
 	select SUPPORT_SPL
 	select SPL
 	select OF_CONTROL
-	select CPU_V7
 	select BLK
 	select DM
 	select SPL_DM

arch/arm/mach-rockchip/Kconfig

@@ -2,6 +2,7 @@ if ARCH_ROCKCHIP
 
 config ROCKCHIP_RK3288
 	bool "Support Rockchip RK3288"
+	select CPU_V7
 	help
 	  The Rockchip RK3288 is a ARM-based SoC with a quad-core Cortex-A17
 	  including NEON and GPU, 1MB L2 cache, Mali-T7 graphics, two
@@ -11,6 +12,7 @@ config ROCKCHIP_RK3288
 
 config ROCKCHIP_RK3036
 	bool "Support Rockchip RK3036"
+	select CPU_V7
 	help
 	  The Rockchip RK3036 is a ARM-based SoC with a dual-core Cortex-A7
 	  including NEON and GPU, Mali-400 graphics, several DDR3 options