usb: typec: remove set but not used variables 'snk_ma, min_mv'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/usb/typec/tcpm/tcpm.c: In function 'tcpm_pd_select_pps_apdo':
drivers/usb/typec/tcpm/tcpm.c:2212:39: warning:
 variable 'snk_ma' set but not used [-Wunused-but-set-variable]

drivers/usb/typec/tcpm/tcpm.c: In function 'tcpm_pd_build_pps_request':
drivers/usb/typec/tcpm/tcpm.c:2405:37: warning:
 variable 'min_mv' set but not used [-Wunused-but-set-variable]

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>