dra7xx_evm: Add QSPI_4 support, qspiboot build target
We previously only supported QSPI_1 (single) support. Add QSPI_4 (quad)
read support as well. This means we can be given one of two boot device
values, but don't care which it is, so perform a fixup on the QSPI_4
value. We add a qspiboot build target to better show how you would use
QSPI as a boot device in deployment. When we boot from QSPI, we can
check the environment for 'boot_os' to control Falcon Mode.
Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Tom Rini <trini@ti.com>