spi: prefix modalias with "spi:"

spi: prefix modalias with "spi:"

This makes it consistent with other buses (platform, i2c, vio, ...).  I'm
not sure why we use the prefixes, but there must be a reason.

This was easy enough to do it, and I did it.

Signed-off-by: Anton Vorontsov <[email protected]>
Cc: David Brownell <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Jean Delvare <[email protected]>
Cc: Ben Dooks <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Dmitry Torokhov <[email protected]>
Cc: Samuel Ortiz <[email protected]>
Cc: "John W. Linville" <[email protected]>
Acked-by: Mike Frysinger <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>