Current implementation of QSPI in SPI mode was available only for MCUs
that do not have standard SPI at all. MCUs with both QSPI and SPI can
however also use QSPI in SPI mode and thus have one more SPI bus. This
commit adds required defines and config options to support QSPI in SPI
mode for all SAMv7 MCUs.
Signed-off-by: Michal Lenc <michallenc@seznam.cz>