arm: mach-omap2/omap3/clock.c: Enable all GPIO with CMD_GPIO

When CMD_GPIO is enabled the command 'gpio status -a' can cause
a hang or reboot if GPIO banks are not enabled, because it scans
all banks.  This patch enables all GPIO banks so 'gpio status -a'
can fully execute.

Signed-off-by: Adam Ford <aford173@gmail.com>