klp-build: Reject patches to realmode

Realmode code is compiled as a separate 16-bit binary and embedded into
the kernel image via rmpiggy.S.  It can't be livepatched.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

scripts/livepatch/klp-build

@@ -357,7 +357,7 @@ check_unsupported_patches() {
 
 		for file in "${files[@]}"; do
 			case "$file" in
-				lib/*|*/vdso/*|*.S)
+				lib/*|*/vdso/*|*/realmode/rm/*|*.S)
 					die "${patch}: unsupported patch to $file"
 					;;
 			esac