ARM: align PIC offset pools to 4 bytes

When building Thumb2 code, the end of a function, where the PIC
offsets are placed, need not be aligned.  Although the values
are only accessed with instructions allowing unaligned addresses,
keeping them aligned is preferable.
Signed-off-by: Mans Rullgard <mans@mansr.com>

libavutil/arm/asm.S

@@ -66,6 +66,7 @@ ELF     .eabi_attribute 25, \val
         .set            .Lpic_gp, 0
     .macro endfunc
       .if .Lpic_idx
+        .align          2
         .altmacro
         put_pic         %(.Lpic_idx - 1)
         .noaltmacro