m25p80: Commit "allow arbitrary OF matching for "jedec,spi-nor"" breaks module autoloading

[Heiner Kallweit <hkallweit1@gmail.com>]

Seems like commit 43163022927b6e7d202a7e6f939c3f392465494d
(allow arbitrary OF matching for "jedec,spi-nor") broke autoloading
of the m25p80 module.
MODALIAS is "spi:spi-nor" and removing "spi-nor" as device alias
prevents module autoloading.

Of course we could revert the removal of the "spi-nor" device alias.
However it might be better to switch to DT-based matching for
DT-configured devices.

Adding a call to of_device_uevent_modalias to spi_uevent in spi.c
solved the issue for me, drawback however is that just the first
"compatible" value is used as modalias. In case of m25p80 this means
that "jedec,spi-nor" has to be the first "compatible" value.
This constraint might be too strict ..

Having said that I'm not sure what could be a better way to fix
the issue than just re-introducing the "spi-nor" device alias.