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

Fixes the same issue as reported for microblaze here
http://autobuild.buildroot.net/results/f49/f4914bb3999c8a7a0c0a2afdac5de40fb9058372/



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

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Anton Kolesov <akolesov@synopsys.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>