arm: omap3: Fix beagleboard SPL boot hangup (GPIO clocks not enabled)

arm: omap3: Fix beagleboard SPL boot hangup (GPIO clocks not enabled)

Patch f33b9bd3
[arm: omap3: Enable clocks for peripherals only if they are used]
breaks SPL booting on Beagleboard. Since some gpio input's are
read to detect the board revision. But with this patch above, the
clocks to the GPIO subsystems are not enabled per default any more.
The GPIO banks need to be configured specifically now.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Tom Rini <trini@ti.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>