Add command to restart the modem

Bug: 175824420
Test: adb shell cmd phone restart-modem
Change-Id: I2c23d42954c7eebe4efafc6c6b938a3c0155155f
Merged-In: I2c23d42954c7eebe4efafc6c6b938a3c0155155f
(cherry picked from commit 54af4630d9e5d687aa07bb180c75c3d3a94136f5)
1 file changed