ARM: fix vp8 neon with pic enabled

The assembler emits literal pools too far from the load instructions,
so we must do it explicitly at a suitable location.

Signed-off-by: Mans Rullgard <mans@mansr.com>
(cherry picked from commit 8b454c352f)

libavcodec/arm/vp8dsp_neon.S

@@ -1294,6 +1294,8 @@ function ff_put_vp8_epel8_h4v6_neon, export=1
         pop             {r4,pc}
 endfunc
 
+.ltorg
+
 function ff_put_vp8_epel4_v6_neon, export=1
         sub             r2,  r2,  r3,  lsl #1
         push            {r4,lr}