Blackfin arch: Add proper -mcpu option according to the cpu and silicon revision configuration

Add silicon revision "any" and "none". Add proper -mcpu option according
to the cpu and silicon revision configuration.

Need update to use latest Blackfin cross compile toolchain.

Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/include/asm-blackfin/processor.h b/include/asm-blackfin/processor.h
index aba2b30..6bb3e0d 100644
--- a/include/asm-blackfin/processor.h
+++ b/include/asm-blackfin/processor.h
@@ -124,6 +124,10 @@
 	return 4;
 #elif defined(CONFIG_BF_REV_0_5)
 	return 5;
+#elif defined(CONFIG_BF_REV_ANY)
+	return 0xffff;
+#else
+	return -1;
 #endif
 }