um: move asm/desc.h into arch/x86/um/asm

its only purpose is to shadow the x86 asm/desc.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/arch/um/include/asm/desc.h b/arch/x86/um/asm/desc.h
similarity index 100%
rename from arch/um/include/asm/desc.h
rename to arch/x86/um/asm/desc.h