mkbootimg: Add --dt parameter to specify DT image

New optional --dt parameter to specify a kernel device
tree image.

Change-Id: Ie29a11cbf4138426bfd19ae486d69a5fcbd8f442
mkbootimg: fixing the typecast issue

Change-Id: Ic375089ecce7aed3f9968e5e0b48e8ae0df66d83
mkbootimg: Support 32K 64K and 128K pagesizes

Signed-off-by: ChampionSwimmer <android@championswimmer.tk>
Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I0ee608b74a1daefe536b9247f99368f3e043f93d