package/xenomai: disable for cortex-M cpus

Following include/asm-arm/features.h, Xenomai doesn't support cortex-M
cpus.

error "Could not find current ARM architecture"

Fixes:
http://autobuild.buildroot.net/results/06a/06a52b2c2c23df595f58feb6b95437fc65a86d31

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/xenomai/Config.in

@@ -1,8 +1,8 @@
 config BR2_PACKAGE_XENOMAI_ARCH_SUPPORTS
 	bool
 	default y
-	depends on BR2_i386 || BR2_x86_64 || BR2_arm || \
-		   BR2_bfin || BR2_powerpc || BR2_sh4
+	depends on BR2_i386 || BR2_x86_64 || (BR2_arm && !BR2_ARM_CPU_ARMV7M) || \
+		BR2_bfin || BR2_powerpc || BR2_sh4
 
 comment "xenomai needs a toolchain w/ threads"
 	depends on !BR2_TOOLCHAIN_HAS_THREADS