soc/amd/common/block/spi/fch_spi_ctrl.c: Fix SPI vendor id code

All solid state devices have vendor id defined by JEDEC specification JEP106,
which originally allocated only 7 bits for it plus parity. When number of
vendors exploded beyond 126, a banking proposition came maintaining
compatibility with older vendors while allowing for 4 extra bits (16 banks)
through the introduction of the concept "Continuation code", denoted by the
byte value of 0x7f.
Examples:
0xfe, 0x60, 0x18, 0x00, 0x00 => vendor 0xfe of bank o
0x7f, 0x7f, 0xfe, 0x60, 0x18 => vendor 0xfe of bank 2

BUG=b:141535133
TEST=Build and boot grunt.

Change-Id: I16c5df70b8ba65017d1a45c79e90a76d1f78550c
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35589
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>

0 files changed, 0 insertions, 0 deletions