spi: Kconfig: fix a spelling mistake & hyphenation

Correct a spelling mistake (reported by codespell).
Also hyphenate "8-bit".
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Link: https://lore.kernel.org/r/20230124233502.23330-1-rdunlap@infradead.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/Kconfig

@@ -247,7 +247,7 @@ config SPI_CADENCE_XSPI
 	  Enable support for the Cadence XSPI Flash controller.
 
 	  Cadence XSPI is a specialized controller for connecting an SPI
-	  Flash over upto 8bit wide bus. Enable this option if you have a
+	  Flash over up to 8-bit wide bus. Enable this option if you have a
 	  device with a Cadence XSPI controller and want to access the
 	  Flash as an MTD device.