This unifies the two different pbi files. With our approach for QSPI
booting differences in the pbi files are not necessary:

- We do not do execute in place for QSPI, so we do not need different
  image execution addresses
- Setting up the QSPI clock doesn't hurt even for SD boot

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>