u-boot-denx: Rename u-boot.inc -> u-boot-denx.inc

This way it wont interfare with other non-beagle BSPs
since u-boot.inc is also available in OE-Core

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Merge pull request #1 from kraj/master

u-boot-denx: Rename u-boot.inc -> u-boot-denx.inc