nicintel_spi.c: Refactor singleton states into reentrant pattern

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

This patch also drops `nicintel` prefix from spi master struct member.

This is one of the steps on the way to move spi_master data
memory management behind the initialisation API, for more
context see other patches under the same topic "register_master_api".

BUG=b:185191942
TEST=builds

Change-Id: I385d3ced19dfe6453ccc4128a7b792c2dce3a449
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54995
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
1 file changed