Correct FPU settings traceback found by IAR

Fixes #9974

The error was that the Asymmetric CPUs were assumed to have the same
structure as the Symmetric CPUs. This is clearly false.

This PR changes the FPU detection of Asymmetric CPUs to find the correct
core and use it's cpu settings.

    [x] Fix
    [ ] Refactor
    [ ] Target update
    [ ] Functionality change
    [ ] Docs update
    [ ] Test update
    [ ] Breaking change

tools/export/cmsis/__init__.py

@@ -31,6 +31,9 @@ class DeviceCMSIS():
 
     Encapsulates target information retrieved by arm-pack-manager"""
 
+    # TODO: This class uses the TARGET_MAP. Usage of the target map may
+    # not work in the online compiler or may work but give the incorrect
+    # information.
     CACHE = Cache(True, False)
     def __init__(self, target):
         target_info = self.check_supported(target)
@@ -44,10 +47,14 @@ def __init__(self, target):
         )
         self.dname = target_info["name"]
         self.core = target_info["_core"]
+        self.dfpu = None
         try:
             self.dfpu = target_info['processor']['Symmetric']['fpu']
         except KeyError:
-            self.dfpu = target_info['processor']['Asymmetric']['fpu']
+            cmsis_core = self.core.replace("F", "").replace("-", "")
+            for proc in target_info['processor']['Asymmetric'].values():
+                if proc['core'] == cmsis_core:
+                    self.dfpu = proc['fpu']
         self.debug, self.dvendor = self.vendor_debug(
             target_info.get('vendor') or target_info['from_pack']['vendor']
         )