arm: v7: Kconfig: Introduce SYS_ARM_CACHE_CP15

Certain ARM architectures like ARMv7-A, ARMv7-R has support for
enabling caches using CP15 registers. To have a common support
for all these architectures, introduce a Kconfig symbol
SYS_ARM_CACHE_CP15 that selects cache-cp15.c

Tested-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 77a3be4..655727f 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -61,11 +61,7 @@
 endif
 
 obj-y	+= cache.o
-ifndef CONFIG_ARM64
-ifndef CONFIG_CPU_V7M
-obj-y	+= cache-cp15.o
-endif
-endif
+obj-$(CONFIG_SYS_ARM_CACHE_CP15)	+= cache-cp15.o
 
 obj-y	+= psci-dt.o