[POWERPC] Made FSL Book-E PMC support more generic

Some of the more recent e300 cores have the same performance monitor
implementation as the e500.  e300 isn't book-e, so the name isn't
really appropriate.  In preparation for e300 support, rename a bunch
of fsl_booke things to say fsl_emb (Freescale Embedded Performance Monitors).

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>