[OE-core] [PATCH] feature-arm-thumb.inc: Suppress false warning

[Jacob Kroon]

If a recipe does not explicitly set ARM_INSTRUCTION_SET, then there is no
need to throw a warning:

  WARNING: Recipe 'foobar' selects ARM_INSTRUCTION_SET to be 'None',
           but tune configuration overrides it to 'arm'

Signed-off-by: Jacob Kroon <jacob.kroon at mikrodidakt.se>
---
 meta/conf/machine/include/arm/feature-arm-thumb.inc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/meta/conf/machine/include/arm/feature-arm-thumb.inc b/meta/conf/machine/include/arm/feature-arm-thumb.inc
index 670e68e..a94386f 100644
--- a/meta/conf/machine/include/arm/feature-arm-thumb.inc
+++ b/meta/conf/machine/include/arm/feature-arm-thumb.inc
@@ -19,6 +19,8 @@ ARM_THUMB_SUFFIX .= "${@bb.utils.contains('TUNE_FEATURES', 'armv7m', 't2', '', d
 ARM_M_OPT = "${@bb.utils.contains('TUNE_FEATURES', 'arm', '${ARM_THUMB_OPT}', 'thumb', d)}"
 python () {
     selected = d.getVar('ARM_INSTRUCTION_SET', True)
+    if selected == None:
+        return
     used = d.getVar('ARM_M_OPT', True)
     if selected != used:
         pn = d.getVar('PN', True)
-- 
1.9.0