BeagleBoneBlackPkg: Increase FVMAIN Size

Increase FVMAIN Size to 0x400000 to accomodate Intel BDS.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Varad Gautam <varadgautam@gmail.com>
BeagleBoneBlackPkg: Drop BeagleBoneBlack BDS

Moved to Intel BDS. Remove local BDS.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Varad Gautam <varadgautam@gmail.com>