Fix out-of-date OC_ARM_ASM_ARMV6 usage.

This was ultimately named OC_ARM_ASM_MEDIA instead.
It shouldn't have mattered in this case, as it shouldn't be possible to get
 OC_ARM_ASM_MEDIA without OC_ARM_ASM_EDSP, but clean it up anyway.

svn path=/trunk/theora/; revision=17646