avcodec/x86/bswapdsp: Avoid aligned vs unaligned codepaths for AVX2

For modern cpus (like those supporting AVX2) loads and stores
using the unaligned versions of instructions are as fast
as aligned ones if the address is aligned, so remove
the aligned AVX2 version (and the alignment check) and just
use the unaligned one.

Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/x86/bswapdsp.asm

@@ -100,10 +100,15 @@ SECTION .text
 
 ; void ff_bswap_buf(uint32_t *dst, const uint32_t *src, int w);
 %macro BSWAP32_BUF 0
-%if cpuflag(ssse3)||cpuflag(avx2)
+%if cpuflag(avx2)
 cglobal bswap32_buf, 3,4,3
+    vbroadcasti128  m2, [pb_bswap32]
+    BSWAP_LOOPS  u
+%else
+%if cpuflag(ssse3)
+cglobal bswap32_buf, 3,4,3
+    mova     m2, [pb_bswap32]
     mov      r3, r1
-    VBROADCASTI128  m2, [pb_bswap32]
 %else
 cglobal bswap32_buf, 3,4,5
     mov      r3, r1
@@ -115,6 +120,7 @@ cglobal bswap32_buf, 3,4,5
     jmp      .left
 .start_align:
     BSWAP_LOOPS  a
+%endif
 .left:
 %if cpuflag(ssse3)
     test     r2d, 2