numa: Move numa implementation to common code

ARM64 numa implementation is generic enough that RISC-V can reuse that
implementation with very minor cosmetic changes. This will help both
ARM64 and RISC-V in terms of maintanace and feature improvement

Move the numa implementation code to common directory so that both ISAs
can reuse this. This doesn't introduce any function changes for ARM64.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 040be48..dbd88e2 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -213,4 +213,10 @@
 	  appropriate scaling, sysfs interface for reading capacity values at
 	  runtime.
 
+config GENERIC_ARCH_NUMA
+	bool
+	help
+	  Enable support for generic NUMA implementation. Currently, RISC-V
+	  and ARM64 use it.
+
 endmenu