Since commit 6c364062 ("spi: core: Add support for registering SPI
slave controllers") SPI slave is also supported, so remove the old
comments that say SPI slave is unsupported.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark Brown <broonie@kernel.org>