powerpc/boot: Check for ld-option support

Commit 579aee9 ("powerpc: suppress some linker warnings in recent linker versions")
enabled support to add linker option "--no-warn-rwx-segments",
if the version is greater than 2.39. Similar build warning were
reported recently from linker version 2.35.2.

ld: warning: arch/powerpc/boot/zImage.epapr has a LOAD segment with RWX permissions
ld: warning: arch/powerpc/boot/zImage.pseries has a LOAD segment with RWX permissions

Fix the warning by checking for "--no-warn-rwx-segments"
option support in linker to enable it, instead of checking
for the version range.

Fixes: 579aee9 ("powerpc: suppress some linker warnings in recent linker versions")
Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Closes: https://lore.kernel.org/linuxppc-dev/61cf556c-4947-4bd6-af63-892fc0966dad@linux.ibm.com/
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250401004218.24869-1-maddy@linux.ibm.com

arch/powerpc/boot/wrapper

@@ -234,10 +234,8 @@ fi
 
 # suppress some warnings in recent ld versions
 nowarn="-z noexecstack"
-if ! ld_is_lld; then
-	if [ "$LD_VERSION" -ge "$(echo 2.39 | ld_version)" ]; then
-		nowarn="$nowarn --no-warn-rwx-segments"
-	fi
+if [ $(${CROSS}ld -v --no-warn-rwx-segments &>/dev/null; echo $?) -eq 0 ]; then
+	nowarn="$nowarn --no-warn-rwx-segments"
 fi
 
 platformo=$object/"$platform".o