spi: bcmbca-hsspi: Add driver for newer HSSPI controller

The newer BCMBCA SoCs such as BCM6756, BCM4912 and BCM6855 include an
updated SPI controller that add the capability to allow the driver to
control chip select explicitly. Driver can control and keep cs low
between the transfers natively. Hence the dummy cs workaround or prepend
mode found in the bcm63xx-hsspi driver are no longer needed and this new
driver is much cleaner.

Port from linux patch:
Link: https://lore.kernel.org/r/20230209200246.141520-15-william.zhang@broadcom.com
Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 7e71c5a..854b8b8 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -107,6 +107,15 @@
 	  access the SPI NOR flash on platforms embedding this Broadcom
 	  SPI core.
 
+config BCMBCA_HSSPI
+	bool "BCMBCA HSSPI driver"
+	depends on ARCH_BCMBCA && HAVE_SPI_CS_CTRL
+	help
+	  This enables support for the High Speed SPI controller present on
+	  newer Broadcom BCMBCA SoCs. These SoCs include an updated SPI controller
+	  that adds the capability to allow the driver to control chip select
+	  explicitly.
+
 config BCM63XX_SPI
 	bool "BCM6348 SPI driver"
 	depends on ARCH_BMIPS