buspirate: Add psus option

This change adds a 'psus=<on|off>' option, to control the external Vcc
state of the bus pirate, allowing hardware where the SPI flash chip is
powered by the 3V3/5V lines directly.

Change-Id: I8a7d4b40c0f7f04f6976f6757f05b61f2c9958f9
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/54887
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/71389
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed