net: wwan: iosm: fix compilation warning

curr_phase is unused. Removed the dead code.

Fixes: 8d9be063 ("net: wwan: iosm: transport layer support for fw flashing/cd")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>