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>
1 file changed