disable stringop truncation warnings for now

commit 217c3e0196758662aa0429863b09d1c13da1c5d6 upstream.

They are too noisy

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>