ARM: 7859/1: debug: Create CONFIG_DEBUG_MSM_UART and re-organize the selects for MSM

Create the hidden config DEBUG_MSM_UART and clean-up
the default selection for CONFIG_DEBUG_LL_INCLUDE.

Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>