serprog: add SPI support

Adds a new opcode (0x13) that just relays SPI bytes and wires it up to be
usable within serprog.c. Checks for mandatory opcodes are moved around and
changed a bit, but non-SPI programmers should not be harmed by this patch.

Corresponding to flashrom svn r1442.

Signed-off-by: Urja Rannikko <urjaman@gmail.com>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
3 files changed