ENGR00215228-12: Move scatter/gather cache coherence into chained function.

ENGR00215228-12: Move scatter/gather cache coherence into chained function.

Last driver revisions began to incorporate optimized mapping functions
for scatter/gather list management, and then centralized them as inlinable
functions usable from multiple modules. Since these became more globally
useful, moved the coupled cache-coherence functions out of the mainline code
and into the inlined ones for simplification.

Signed-off-by: Steve Cornelius <steve.cornelius@freescale.com>