Create a new u-boot-master port to consolidate all different u-boot
ports. Switch to using my github branch for grabbing ports. Convert
the Beaglebone family of ports over to using the new setup.
Sanity Test Results
sysutils/u-boot-master:
Description file does not exist:
'/usr/local/PORTS-head/sysutils/u-boot-master/pkg-descr' (result of make -V
DESCR)