Platform: rp2350: Add rwx linker flag conditionally for GNUARM

--no-warn-rwx-segments linker flag only
handled in GCC12 and above.

Signed-off-by: Dávid Házi <david.hazi@arm.com>
Change-Id: I1a653b54f616f4eaad0ab08dd0961c4c90215a0d
2 files changed