linux: config.in: add comment for Arm Cortex-M

When binutils > 2.28 are selected on Arm Cortex-M cpu,
linux kernel does not boot due to a new implementation
of 'adr pseudo instruction' on binutils.

Bugzilla thread: https://bugs.busybox.net/show_bug.cgi?id=11051

Signed-off-by: Christophe Priouzeau <christophe.priouzeau@st.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

linux/Config.in

@@ -8,6 +8,10 @@ config BR2_LINUX_KERNEL
 
 if BR2_LINUX_KERNEL
 
+comment "Linux kernel will not boot with binutils >= 2.29"
+	depends on BR2_ARM_CPU_ARMV7M
+	depends on !BR2_BINUTILS_VERSION_2_28_X
+
 # Packages that need to have a kernel with support for loadable modules,
 # but do not use the kernel-modules infrastructure, should select that
 # option.