Fixes: unaligned memory access
Fixes: signal_sigsegv_3344165_576_cov_3406448105_DBLK_A_MAIN10_VIXS_2.bit

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Suggested-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>