MAINTAINERS: add qspi to Polarfire SoC entry

Add the qspi driver to existing Polarfire SoC entry.

Signed-off-by: Naga Sureshkumar Relli <nagasuresh.relli@microchip.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220808064603.1174906-5-nagasuresh.relli@microchip.com


Signed-off-by: Mark Brown <broonie@kernel.org>