ARM: add missing preserve8 directives

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@21952 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/arm/dsputil_armv6.S

@@ -20,6 +20,8 @@
 
 #include "asm.S"
 
+        preserve8
+
         .text
 
 .macro  call_2x_pixels  type, subp

libavcodec/arm/mdct_neon.S

@@ -21,6 +21,8 @@
 
 #include "asm.S"
 
+        preserve8
+
         .text
 
 #define ff_fft_calc_neon X(ff_fft_calc_neon)