amlogic: Move thermal code to common directory

As for most of the Amlogic code, this is common between the Amlogic
SoCs. Move the code to the common directory.

Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Change-Id: Id3f0073ff1f0b9ddbe964f80303323ee4a2f27b0
diff --git a/plat/amlogic/gxbb/platform.mk b/plat/amlogic/gxbb/platform.mk
index 7da6468..4c3df1b 100644
--- a/plat/amlogic/gxbb/platform.mk
+++ b/plat/amlogic/gxbb/platform.mk
@@ -33,7 +33,7 @@
 				${AML_PLAT_SOC}/gxbb_pm.c		\
 				${AML_PLAT_COMMON}/aml_scpi.c		\
 				${AML_PLAT_SOC}/gxbb_sip_svc.c		\
-				${AML_PLAT_SOC}/gxbb_thermal.c		\
+				${AML_PLAT_COMMON}/aml_thermal.c	\
 				${GIC_SOURCES}
 
 # Tune compiler for Cortex-A53