x86/constants: fix alignment of pw_255

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/x86/constants.c

@@ -40,7 +40,7 @@ DECLARE_ALIGNED(8,  const uint64_t, ff_pw_53)   =   0x0035003500350035ULL;
 DECLARE_ALIGNED(16, const xmm_reg,  ff_pw_64)   = { 0x0040004000400040ULL, 0x0040004000400040ULL };
 DECLARE_ALIGNED(8,  const uint64_t, ff_pw_96)   =   0x0060006000600060ULL;
 DECLARE_ALIGNED(8,  const uint64_t, ff_pw_128)  =   0x0080008000800080ULL;
-DECLARE_ALIGNED(8,  const xmm_reg,  ff_pw_255)  = { 0x00ff00ff00ff00ffULL, 0x00ff00ff00ff00ffULL };
+DECLARE_ALIGNED(16, const xmm_reg,  ff_pw_255)  = { 0x00ff00ff00ff00ffULL, 0x00ff00ff00ff00ffULL };
 DECLARE_ALIGNED(32, const ymm_reg,  ff_pw_256)  = { 0x0100010001000100ULL, 0x0100010001000100ULL,
                                                     0x0100010001000100ULL, 0x0100010001000100ULL };
 DECLARE_ALIGNED(16, const xmm_reg,  ff_pw_512)  = { 0x0200020002000200ULL, 0x0200020002000200ULL };