ARM: use numeric ID for Tag_ABI_align_preserved

Some old assemblers still in use do not support named tags.
Signed-off-by: Mans Rullgard <mans@mansr.com>

libavutil/arm/asm.S

@@ -52,7 +52,7 @@
 
         .syntax unified
 T       .thumb
-ELF     .eabi_attribute Tag_ABI_align_preserved, 1
+ELF     .eabi_attribute 25, 1           @ Tag_ABI_align_preserved
 
 .macro  function name, export=0
         .set            .Lpic_idx, 0