sg3-utils: disable for blackfin

Suffers from the usual symbol prefixing problems for bfin, it's probably
easy to fix, however no bfin has/will be used for storage apps since
they lack the usual ports for it. Fixes:
http://autobuild.buildroot.net/results/314/31447787e70cd351ce01b7a49ba029758d0c68e5/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/sg3_utils/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_SG3_UTILS
 	bool "sg3-utils"
+	depends on !BR2_bfin # symbol prefixing problems
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	help
 	  Low level utilities for devices that use a SCSI command set.
@@ -15,4 +16,5 @@ config BR2_PACKAGE_SG3_UTILS_PROGS
 endif
 
 comment "sg3-utils needs a toolchain w/ threads"
+	depends on !BR2_bfin
 	depends on !BR2_TOOLCHAIN_HAS_THREADS