Makefile.common: always add rec_arm.cpp if ARCH is arm

We need rec_arm.cpp even if no arm dynarec is used.

Makefile.common

@@ -127,7 +127,6 @@ endif
 ifeq ($(WITH_DYNAREC), arm)
 DYNAREC_USED = 1
 SOURCES_CXX += $(CORE_DIR)/rec-ARM/rec_arm.cpp
-SOURCES_ASM += $(CORE_DIR)/rec-ARM/ngen_arm.S
 endif
 
 ifeq ($(DYNAREC_USED),1)
@@ -140,6 +139,10 @@ SOURCES_CXX += $(CORE_DIR)/hw/sh4/dyna/decoder.cpp \
 
 endif
 
+ifneq (,$(findstring arm, $(ARCH)))
+SOURCES_ASM += $(CORE_DIR)/rec-ARM/ngen_arm.S
+endif
+
 SOURCES_CXX += $(CORE_DIR)/libretro/libretro.cpp \
 					$(CORE_DIR)/libretro/common.cpp