x86: specify CONFIG_USE_PRIVATE_LIBGCC more simply

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/config.mk b/arch/x86/config.mk
index 1e52a5e..38cb7c9 100644
--- a/arch/x86/config.mk
+++ b/arch/x86/config.mk
@@ -29,6 +29,4 @@
 LDFLAGS_FINAL += --wrap=__moddi3 --wrap=__umoddi3
 
 export NORMAL_LIBGCC = $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
-PREFIXED_LIBGCC = $(OBJTREE)/arch/$(ARCH)/lib/$(shell basename $(NORMAL_LIBGCC))
-
-CONFIG_USE_PRIVATE_LIBGCC=$(shell dirname $(PREFIXED_LIBGCC))
+CONFIG_USE_PRIVATE_LIBGCC := arch/x86/lib