vlc: fix build on or1k

vlc: fix build on or1k

vlc 3.0.4 is also affected by gcc bug internal compiler error on or1k

hw/vaapi/vlc_vaapi.c: In function 'pool_pic_destroy_cb':
hw/vaapi/vlc_vaapi.c:568:1: internal compiler error: in merge_overlapping_regs, at regrename.c:304
 }

Fixes:
 - http://autobuild.buildroot.org/results/771e88e7fb06714dd4b7246f82b95dffcedde343

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>