powerpc/boot: Check for ld-option support

Commit 579aee9f ("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: 579aee9f ("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