package/libnss: fix build failure on arm32 arch not armv7

package/libnss: fix build failure on arm32 arch not armv7

NSS assumes that every neon arm32 build is an armv7, but this is
not always true(i.e. build arm32 for armv8), so let's add a patch to
remove -march=armv7 flag when building gcm-arm32-neon.c

Fixes:
http://autobuild.buildroot.net/results/464/464044fda2850123339de6c8071374e380636ee0/

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>