Because we only ever call Pos_ReadDirect (and through that, DataRead<T>)
from JIT generated code, the compiler may not get the heads-up to properly
prepare for run-time instantiation of those template functions.
Explicitly instantiating Pos_ReadDirect gets around that issue.
Also force DataRead* inline as gcc didn't always do that itself when the
DataRead functions in turn were called from (other) template functions.
git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@5902 8ced0084-cf51-0410-be5f-012b33b47a6e