spi: bcm-qspi: shut up warning about cfi header inclusion

When CONFIG_MTD_CFI is disabled, we get a warning for this spi driver:

include/linux/mtd/cfi.h:76:2: #warning No CONFIG_MTD_CFI_Ix selected. No NOR chip support can work. [-Werror=cpp]

The problem here is a layering violation that was fixed in mainline kernels with
a larger rework in commit 054e532f ("spi: bcm-qspi: Remove hardcoded settings
and spi-nor.h dependency"). We can't really backport that to stable kernels, so
this just adds a Kconfig dependency to make it either build cleanly or force it
to be disabled.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/spi/Kconfig

@@ -156,6 +156,7 @@ config SPI_BCM63XX_HSSPI
 config SPI_BCM_QSPI
 	tristate "Broadcom BSPI and MSPI controller support"
 	depends on ARCH_BRCMSTB || ARCH_BCM || ARCH_BCM_IPROC || COMPILE_TEST
+	depends on MTD_NORFLASH
 	default ARCH_BCM_IPROC
 	help
 	  Enables support for the Broadcom SPI flash and MSPI controller.