spi_flash: Make a deep copy of spi_slave structure

spi_flash: Make a deep copy of spi_slave structure

Commit 36b81af (spi: Pass pointer to spi_slave structure in
spi_setup_slave) changes the way spi_setup_slave handles the spi_slave
structure. Instead of expecting spi controller drivers to maintain
spi_slave structure in CAR_GLOBAL/data section, caller is expected to
manage the spi_slave structure. This requires that spi_flash drivers
maintain spi_slave structure and flash probe function needs to make a
copy of the passed in spi_slave structure.

This change fixes the regression on Lenovo X230 and other mainboards.

Change-Id: I0ad971eecaf3bfe301e9f95badc043193cc27cab
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17728
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Iru Cai <mytbk920423@gmail.com>