Renamed mx2/imx27 to mxc.

Renamed all functions, enums, structs and defines from mx2/imx27 to mxc. This is in preparation of adding support for mx35 NFC(v2).

Change-Id: I92ad23f0cfab605215bbf0d5846c5c288423facf
Signed-off-by: Erik Ahlén <erik.ahlen@avalonenterprise.com>
Reviewed-on: http://openocd.zylin.com/267


Tested-by: jenkins
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>