it85spi.c: Refactor singleton states into reentrant pattern

Move global singleton states into a struct and store within
the spi_master data field for the life-time of the driver.

BUG=b:172876667
TEST=builds

Change-Id: I389d34d62e753c012910aa5ff24a496b24a4753c
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/47655
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Daniel Kurtz <djkurtz@google.com>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
1 file changed