[armhf] add the rt featureset, which adds support for PREEMPT_RT (Closes #719547)

This adds support for PREEMPT_RT by adding two new featureset: none and
rt. For now the rt featureset supports armmp only, support for lpae
might be added later. the none featureset supports both flavours armmp
and armmp-lpae.

debian/changelog

@@ -1,7 +1,12 @@
 linux (4.18~rc5-1~exp2) UNRELEASED; urgency=medium
 
+  [ Uwe Kleine-König ]
   * [arm64] enable RTC_DRV_PCF8563 for Odroid-C2
 
+  [ Romain Perier ]
+  * [armhf] add the rt featureset, which adds support for PREEMPT_RT
+    (Closes #719547)
+
  -- Uwe Kleine-König <ukleinek@debian.org>  Sat, 21 Jul 2018 16:52:01 +0200
 
 linux (4.18~rc5-1~exp1) experimental; urgency=medium

debian/config/armhf/defines

@@ -1,7 +1,7 @@
 [base]
-flavours:
- armmp
- armmp-lpae
+featuresets:
+ none
+ rt
 kernel-arch: arm
 
 [build]

debian/config/armhf/none/defines

@@ -0,0 +1,4 @@
+[base]
+flavours:
+ armmp
+ armmp-lpae

debian/config/armhf/rt/defines

@@ -0,0 +1,3 @@
+[base]
+flavours:
+ armmp