Fix "Potential leak of memory pointed to by 'cortex_m'"
and test for NULL return from calloc in cortex_m_target_create()
Change-Id: I4d2bb5bccc57f0ed60696f3d588297a858b8ea60
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4881
Tested-by: jenkins
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>