drivers: renesas: pwrc: Move to common

Move pwrc driver code to common directory, so that the same
code can be re-used by both R-Car Gen3 and RZ/G2 platforms.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Change-Id: I75d91a44d872fe2296b15c700efacd5721385363
diff --git a/plat/renesas/common/common.mk b/plat/renesas/common/common.mk
index 82f4d7d..6e8786d 100644
--- a/plat/renesas/common/common.mk
+++ b/plat/renesas/common/common.mk
@@ -94,6 +94,8 @@
 			lib/cpus/aarch64/cortex_a53.S			\
 			lib/cpus/aarch64/cortex_a57.S			\
 			plat/common/plat_psci_common.c			\
+			drivers/renesas/common/pwrc/call_sram.S		\
+			drivers/renesas/common/pwrc/pwrc.c		\
 			drivers/renesas/common/common.c			\
 			drivers/arm/cci/cci.c