Blackfin: move default boot SPI CS to common code

Move the default SPI CS that we boot from into common code so that it can
be used in other SPI drivers and environment settings.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/asm-blackfin/blackfin-config-pre.h b/include/asm-blackfin/blackfin-config-pre.h
index a1fae5c..9df01ad 100644
--- a/include/asm-blackfin/blackfin-config-pre.h
+++ b/include/asm-blackfin/blackfin-config-pre.h
@@ -60,4 +60,13 @@
 }
 #endif
 
+/* Define the default SPI CS used when booting out of SPI */
+#if defined(__ADSPBF531__) || defined(__ADSPBF532__) || defined(__ADSPBF533__) || \
+    defined(__ADSPBF538__) || defined(__ADSPBF539__) || defined(__ADSPBF561__) || \
+    defined(__ADSPBF51x__)
+# define BFIN_BOOT_SPI_SSEL 2
+#else
+# define BFIN_BOOT_SPI_SSEL 1
+#endif
+
 #endif