klp-build: Reject patches to vDSO

vDSO code runs in userspace and can't be livepatched.  Such patches also
cause spurious "new function" errors due to generated files like
vdso*-image.c having unstable line numbers across builds.

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/*|*.S)
+				lib/*|*/vdso/*|*.S)
 					die "${patch}: unsupported patch to $file"
 					;;
 			esac