Introduce MORTSGNA_ARMV7_TUNE to reduce armv7a build variant optionally

It depends on user's needs - and is not a pinned distro decision.

Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>

conf/distro/include/mortsgna-armv7-tune.inc

@@ -0,0 +1,17 @@
+def armv7_tune_handler(d):
+    tune = d.getVar('DEFAULTTUNE', True)
+    # set MORTSGNA_ARMV7_TUNE="1" in your local.conf to reduce all cortex variants
+    # to common tune value
+    if d.getVar('MORTSGNA_ARMV7_TUNE', True) == '1':
+        features = d.getVar('TUNE_FEATURES', True).split()
+        if 'armv7a' in features or 'armv7ve' in features:
+            tune = 'armv7athf'
+            if 'bigendian' in features:
+                tune += 'b'
+            if 'neon' in features:
+                tune += '-neon'
+        else:
+            tune = d.getVar('DEFAULTTUNE', True)
+
+    return tune
+