crossystem: arm: fix incorrect mainfw_act output
crossystem: arm: fix incorrect mainfw_act output

BUG=chromium-os:15626
TEST=manual

when not recovery boot
$ [ $(crossystem mainfw_act) = "A" ] || [ $(crossystem mainfw_act) = "B" ]

when recovery boot
$ [ $(crossystem mainfw_act) = "recovery" ]

Change-Id: I3917106b61e2979d8cb07f01fd0cec044ae725cb
Reviewed-on: http://gerrit.chromium.org/gerrit/1345
Tested-by: Che-Liang Chiou <57969107b634cf11cb64e9d768fd46929066adab@chromium.org>
Reviewed-by: Hung-Te Lin <8a7fce4940baad93a69f5073b383c85deed9d9c4@chromium.org>

marineam/seismograph,geekboxzone/mmallow_external_vboot_reference,coreboot/vboot,ccaapton/vboot_reference,acorn-marvell/vboot_reference,ionave/seismograph,coreboot/vboot,marineam/seismograph,coreboot/vboot,coreboot/vboot,marineam/seismograph,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,marineam/seismograph,ccaapton/vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,ccaapton/vboot_reference,ionave/seismograph,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,acorn-marvell/vboot_reference,acorn-marvell/vboot_reference,ionave/seismograph,ccaapton/vboot_reference