msm: fix compile failure when no debug uart is selected

msm: fix compile failure when no debug uart is selected

If the board has a debug uart the user is given a choice of which
uart to use. The user can also select NONE, which means not to use one.
In most of our header files when NONE is selected nothing is defined
for MSM_DEBUG_UART_PHYS or MSM_DEBUG_UART_BASE. This causes a compile
failure in debug-macro.S which expect something to be defined there.

Example of the failure,

arch/arm/kernel/built-in.o: In function `hexbuf':
linux-2.6/arch/arm/kernel/debug.S:186: undefined reference to `MSM_DEBUG_UART_PHYS'
linux-2.6/arch/arm/kernel/debug.S:186: undefined reference to `MSM_DEBUG_UART_BASE'

This fixes the compile failure by adding an ifdef to debug-macro.S
that removes all the debug uart code in the case of NONE.

Signed-off-by: Daniel Walker <dwalker@codeaurora.org>