d2att: remove all L series bootloaders

They're much too old and people have had plenty of time to upgrade.

Change-Id: I946507f19802a74b9598ddd6ccdde07b23aa9cc2
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_device_samsung_d2att into cm-11.0

Conflicts:
	board-info.txt

Change-Id: Iebf055b8b75872afb42aa7fbff3c5abbe76c2d23
add SC06DOMBMK2 as valid bootloader

Change-Id: Icb8700d5267300223361564f89ef2ebf5e45df4e