amlogic: Move the SIP SVC code to common directory

The code is the same between GXBB and GXL. Move it to the common source
directory.

Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Change-Id: I875689a6fd029971aa755fc2725217e90ed06b6c
diff --git a/plat/amlogic/gxl/platform.mk b/plat/amlogic/gxl/platform.mk
index 1c41cd5..f4d3235 100644
--- a/plat/amlogic/gxl/platform.mk
+++ b/plat/amlogic/gxl/platform.mk
@@ -35,7 +35,7 @@
 				${AML_PLAT_COMMON}/aml_mhu.c		\
 				${AML_PLAT_SOC}/gxl_pm.c		\
 				${AML_PLAT_COMMON}/aml_scpi.c		\
-				${AML_PLAT_SOC}/gxl_sip_svc.c		\
+				${AML_PLAT_COMMON}/aml_sip_svc.c	\
 				${AML_PLAT_COMMON}/aml_thermal.c	\
 				drivers/amlogic/crypto/sha_dma.c	\
 				${GIC_SOURCES}