xtensa: only use auto-litpools for little endian

mk/vars.mk

@@ -232,9 +232,11 @@ endif
 
 # special architecture optimization flags
 ifeq ($(ADK_TARGET_ARCH_XTENSA),y)
+ifeq ($(ADK_TARGET_BIG_ENDIAN),)
 TARGET_CFLAGS+=		-mlongcalls -mauto-litpools
 TARGET_CXXFLAGS+=	-mlongcalls -mauto-litpools
 endif
+endif
 ifeq ($(ADK_TARGET_ARCH_MICROBLAZE),y)
 TARGET_CFLAGS+=		-mxl-barrel-shift
 TARGET_CXXFLAGS+=	-mxl-barrel-shift