target: fix incorrect arm cpu monitor mode encoding

target: fix incorrect arm cpu monitor mode encoding

According to the "Arm Arch Ref Manual ARMv7-a and ARMv7-R edition" the
CPSR encoding for Monitor mode is 0b10110 (22) not 0b11010 (26) as is
currently used.

Change-Id: I73373a0029a81abc92febf518b88bf0dd4dec1fa
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/2081
Reviewed-by: Jörg Wunsch <openocd@uriah.heep.sax.de>
Tested-by: jenkins
Reviewed-by: Younes REGAIEG <y.regaieg@gmail.com>
Reviewed-by: Tim Sander <tim@krieglstein.org>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>