Do not check which flash type the SoC was booted from before
using this driver. Assume that the device tree is correct and use this
driver when it was added to device tree. This also removes a build
dependency to the SoC code.

All device trees I am aware of only have one correct flash device entry
in it. The device tree is anyway bundled with the kernel in all systems
using device tree I know of.

The boot mode can be specified with some pin straps and will select the
flash type the rom code will boot from. One SPI, NOR or NAND flash chip
can be connect to the EBU and used to load the first stage boot loader
from.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>