um: remove redundant 'export LDFLAGS' in arch/x86/Makefile.um

This is already exported by the top-level Makefile.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

arch/x86/Makefile.um

@@ -13,8 +13,6 @@ KBUILD_CFLAGS		+= $(call cc-option,-m32)
 KBUILD_AFLAGS		+= $(call cc-option,-m32)
 LINK-y			+= $(call cc-option,-m32)
 
-export LDFLAGS
-
 LDS_EXTRA		:= -Ui386
 export LDS_EXTRA