gstreamer{,1}: fix unaligned access detection for microblaze

Fixes http://autobuild.buildroot.net/results/f49/f4914bb3999c8a7a0c0a2afdac5de40fb9058372/



Similar to the existing handling for avr32 and xtensa. Also add it for
gstreamer1 for good measure as it was missing there as well.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>