arm: omap_common: expose tps659038 and dra7xx_dplls

expose those two definitions so they can be
used by another board which we're adding in upcoming
patches.

Signed-off-by: Felipe Balbi <balbi@ti.com>
arm: omap: add support for am57xx devices

just add a few ifdefs around because this
device is very similar to dra7xxx.

Signed-off-by: Felipe Balbi <balbi@ti.com>
beagle_x15: add board support for Beagle x15

This is the bare minimum support for Beagle x15
into u-boot. There is still quite some work in
order to get this in good shape, but it's a
start.

Signed-off-by: Felipe Balbi <balbi@ti.com>