spi: add Kconfig entries for SPI4 and SPI5.

The SAM0 series has up to 6 SPI ports.  Add Kconfig options to match.

Similar to the 9033fb2f01, this patch
only defines the fields that are currently used and skips ones like
GPIO and IRQ priority that aren't.

Signed-off-by: Michael Hope <mlhx@google.com>

drivers/spi/Kconfig

@@ -235,6 +235,32 @@ config SPI_3_IRQ_PRI
 	prompt "Port 3 interrupt priority"
 	depends on SPI_3
 
+config SPI_4
+	bool
+	prompt "SPI port 4"
+	default n
+	help
+	  Enable SPI controller port 4.
+
+config SPI_4_NAME
+	string
+	prompt "SPI port 4 device name"
+	depends on SPI_4
+	default "SPI_4"
+
+config SPI_5
+	bool
+	prompt "SPI port 5"
+	default n
+	help
+	  Enable SPI controller port 5.
+
+config SPI_5_NAME
+	string
+	prompt "SPI port 5 device name"
+	depends on SPI_5
+	default "SPI_5"
+
 config SPI_SS_INIT_PRIORITY
 	int "Init priority"
 	depends on SPI_QMSI_SS