mach-snapdragon: of_fixup: Drop USB dr_mode override for RB1/2

mach-snapdragon: of_fixup: Drop USB dr_mode override for RB1/2

The default DIP switch configuration on RB1/2 is to enable flashing
support via USB type-c port either using QDL or fastboot. It's just
cumbersome to get the host mode working in U-Boot via DIP switch toggle
when you need the flashing capability using the type-c port.

So instead lets enable fastboot in U-Boot for RB1/2 boards which is
more useful in the default board DIP switch configuration. This let's
us to drop dr_mode DT fixup.

Signed-off-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250516130854.606067-1-sumit.garg@kernel.org
Signed-off-by: Casey Connolly <casey.connolly@linaro.org>