usb_master: Implement set_erase_command call

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
usb_master: Implement set_custom_erase_command call

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
usb_master: Implement set_write_command call

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
usb_master: Implement set_custom_write_command call

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>