Add ops.write to the hwdep interface. Once the upgrade firmware flash
segment has been erased, writes to the hwdep fd are permitted, and
translated to SCARLETT2_USB_WRITE_SEGMENT commands to the device.
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/ZY65S0ojShSNSeRQ@m.b4.vuSigned-off-by: Takashi Iwai <tiwai@suse.de>