app: fastboot: implement command 'fastboot oem help'
app: fastboot: implement command 'fastboot oem help'

jsr-d10/android_bootable_bootloader_lk,jsr-d10/android_bootable_bootloader_lk,jsr-d10/android_bootable_bootloader_lk,jsr-d10/android_bootable_bootloader_lk,jsr-d10/android_bootable_bootloader_lk