Revert "scripts/setlocalversion: git: Make -dirty check more robust"

This reverts commit 6147b1c.

The reverted patch results in attempted write access to the source
repository, even if that repository is mounted read-only.

Output from "strace git status -uno --porcelain":

getcwd("/tmp/linux-test", 129)          = 16
open("/tmp/linux-test/.git/index.lock", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0666) =
	-1 EROFS (Read-only file system)

While git appears to be able to handle this situation, a monitored
build environment (such as the one used for Chrome OS kernel builds)
may detect it and bail out with an access violation error. On top of
that, the attempted write access suggests that git _will_ write to the
file even if a build output directory is specified. Users may have the
reasonable expectation that the source repository remains untouched in
that situation.

Fixes: 6147b1c ("scripts/setlocalversion: git: Make -dirty check more robust"
Cc: Genki Sky <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Reviewed-by: Brian Norris <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

scripts/setlocalversion

@@ -74,7 +74,7 @@ scm_version()
 		fi
 
 		# Check for uncommitted changes
-		if git status -uno --porcelain | grep -qv '^.. scripts/package'; then
+		if git diff-index --name-only HEAD | grep -qv "^scripts/package"; then
 			printf '%s' -dirty
 		fi