Avoid text relocations in ARM vp8 decoder

Avoid text relocations in ARM vp8 decoder

The current code stores pointers to coefficient tables and loads them to
access the tables contents. As these pointers are stored in the code
sections, it means we end up with text relocations. eu-findtextrel will
thus complain about code not compiled with -fpic/-fPIC.

Since the pointers are stored in the code sections, we can actually cheat
and let the assembler generate relative addressing when accessing the
coefficient tables, and just load their location with adr.

Change-Id: Ib74ae2d3f2bab80b29991355f2dbe6955f38f6ae