Blackfin: bfin_spi: use same gpio cs define as Linux

Linux uses an offset of 8 to switch from hardware cs to a gpio cs,
so have u-boot use the same value.  Also make sure it is public
for boards to access.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/include/asm/config-pre.h b/arch/blackfin/include/asm/config-pre.h
index 4531519..4ce67d4 100644
--- a/arch/blackfin/include/asm/config-pre.h
+++ b/arch/blackfin/include/asm/config-pre.h
@@ -71,6 +71,9 @@
 # define BFIN_BOOT_SPI_SSEL 1
 #endif
 
+/* Define to get a GPIO CS with the Blackfin SPI controller */
+#define MAX_CTRL_CS 8
+
 /* There is no Blackfin/NetBSD port */
 #undef CONFIG_BOOTM_NETBSD
 
diff --git a/drivers/spi/bfin_spi.c b/drivers/spi/bfin_spi.c
index e0ad029..556b97a 100644
--- a/drivers/spi/bfin_spi.c
+++ b/drivers/spi/bfin_spi.c
@@ -35,8 +35,6 @@
 
 #define to_bfin_spi_slave(s) container_of(s, struct bfin_spi_slave, slave)
 
-#define MAX_CTRL_CS 7
-
 #define gpio_cs(cs) ((cs) - MAX_CTRL_CS)
 #ifdef CONFIG_BFIN_SPI_GPIO_CS
 # define is_gpio_cs(cs) ((cs) > MAX_CTRL_CS)