OMAP3: PM: fix UART handling when using no_console_suspend

During the idle/suspend path, we expect the console lock to be held so
that no console output is done during/after the UARTs are idled.

However, when using the no_console_suspend argument on the
command-line, the console driver does not take the console lock.  This
allows the possibility of console activity after UARTs have been
disabled.

To fix, update the current is_suspending() to also check the
console_suspend_enabled flag.

Reported-by: Abhilash Koyamangalath <abhilash.kv@ti.com>
Tested-by: Abhilash Koyamangalath <abhilash.kv@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>