spi: rspi: Use dev_warn_once() instead of open-coding

Use the helper introduced by commit e135303bd5bebcd2 ("device: Add
dev_<level>_once variants") instead of open-coding the same operation.

Signed-off-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
1 file changed