mako: serial console: not write console message if not using earjack-dedugger

flushing console messages into uart is very slow.
If you boot up without connecting the earjack-debugger, skip to
write console message into uart.  So We can reduce the bootup time
by about 2 seconds.  But unfortunately this patch is mako specific
patch, not generic

without this patch:
[    1.001648] msm_serial_hsl: console setup on port #0
[    2.344452] console [ttyHSL0] enabled

with this patch:
[    0.966091] msm_serial_hsl: console setup on port #0
[    0.966854] console [ttyHSL0] enabled

Change-Id: Iba2628fe7b9e08583d98e804ee6bc3bd87aee9a7