clang: Don't look for libgcc

In the case of using clang to build, and having not already enabled the
private libgcc, do not look for it, as it will not be found nor
required.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index 9d8ec9f..166acba 100644
--- a/Makefile
+++ b/Makefile
@@ -894,8 +894,10 @@
 ifeq ($(CONFIG_USE_PRIVATE_LIBGCC),y)
 PLATFORM_LIBGCC = arch/$(ARCH)/lib/lib.a
 else
+ifndef CONFIG_CC_IS_CLANG
 PLATFORM_LIBGCC := -L $(shell dirname `$(CC) $(c_flags) -print-libgcc-file-name`) -lgcc
 endif
+endif
 PLATFORM_LIBS += $(PLATFORM_LIBGCC)
 
 ifdef CONFIG_CC_COVERAGE