tty: msm_smd_tty: Remove useless NULL checks

Clang warns:

../drivers/tty/serial/msm_smd_tty.c:373:19: warning: address of array
'smd_tty[n].dev_name' will always evaluate to 'true'
[-Wpointer-bool-conversion]
                if (!smd_tty[n].dev_name)
                    ~~~~~~~~~~~~^~~~~~~~
../drivers/tty/serial/msm_smd_tty.c:507:39: warning: address of array
'smd_tty[n].ch_name' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        if (n >= MAX_SMD_TTYS || !smd_tty[n].ch_name)
                                 ~~~~~~~~~~~~^~~~~~~
2 warnings generated.

Fixes: d680a245 ("soc: qcom: msm_smd: Add snapshot of Shared memory driver")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Change-Id: Ie45bbd6da088ae77efcf85f2e25c72ccdcdf13bf
Signed-off-by: improbir <ghosh_probir@yahoo.com>