rtos: Freescale MQX rtos support

rtos: Freescale MQX rtos support

ARMv7E-M (CortexM4) architecture

- fix position offset of r2,r3 registers on exception stack
- switch 'calloc' arguments
- remove prototypes of internal function and typedefs
- add NULL check for alloc functions
- remove last line of license "Franklin Street, Fifth Floor"
  because of 'checkpatch' validation
- environment: jlink + twrk60n512

Change-Id: I70840ded15b17dd945ca190ce31e2775078da2d9
Signed-off-by: Marian Cingel <cingel.marian@gmail.com>
Reviewed-on: http://openocd.zylin.com/2353
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>