Blackfin: allow people to select BF51x-0.1 silicon rev

Now that 0.1 of the BF51x is coming out, allow people to build for it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/Kconfig

@@ -274,7 +274,7 @@ config BF_REV_0_0
 
 config BF_REV_0_1
 	bool "0.1"
-	depends on (BF52x || (BF54x && !BF54xM))
+	depends on (BF51x || BF52x || (BF54x && !BF54xM))
 
 config BF_REV_0_2
 	bool "0.2"