mips: m4k alternate pracc code. Patch 4

Now all the functions with only fetch accesses are modified.
The same delay between scans has been added to mips32_pracc_fastdata_xfer(), it should work
at the same scan rates as the other pracc functions, but it needs higher scan_delays
to work.

Change-Id: Ifb31d8ea6de9d22674385782913d221a2494dbbf
Signed-off-by: Salvador Arroyo <sarroyofdez@yahoo.es>
Reviewed-on: http://openocd.zylin.com/1196
Tested-by: jenkins
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>