avocado/utils/cpu.py: more compact implementation of get_cpu_arch()

This shouldn't change the behavior, but is more compact, and at least
for me, is more readable.

And, it happens to make (pure) pylint happier because there aren't
that many 'return' statements.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

avocado/utils/cpu.py

@@ -97,28 +97,20 @@ def get_cpu_arch():
     """
     Work out which CPU architecture we're running on
     """
+    cpu_table = [('^cpu.*(RS64|POWER3|Broadband Engine)', 'power'),
+                 ('^cpu.*POWER4', 'power4'),
+                 ('^cpu.*POWER5', 'power5'),
+                 ('^cpu.*POWER6', 'power6'),
+                 ('^cpu.*POWER7', 'power7'),
+                 ('^cpu.*POWER8', 'power8'),
+                 ('^cpu.*PPC970', 'power970'),
+                 ('ARM', 'arm'),
+                 ('^flags.*:.* lm .*', 'x86_64')]
     cpuinfo = _get_cpu_info()
-
-    if _list_matches(cpuinfo, '^cpu.*(RS64|POWER3|Broadband Engine)'):
-        return 'power'
-    elif _list_matches(cpuinfo, '^cpu.*POWER4'):
-        return 'power4'
-    elif _list_matches(cpuinfo, '^cpu.*POWER5'):
-        return 'power5'
-    elif _list_matches(cpuinfo, '^cpu.*POWER6'):
-        return 'power6'
-    elif _list_matches(cpuinfo, '^cpu.*POWER7'):
-        return 'power7'
-    elif _list_matches(cpuinfo, '^cpu.*POWER8'):
-        return 'power8'
-    elif _list_matches(cpuinfo, '^cpu.*PPC970'):
-        return 'power970'
-    elif _list_matches(cpuinfo, 'ARM'):
-        return 'arm'
-    elif _list_matches(cpuinfo, '^flags.*:.* lm .*'):
-        return 'x86_64'
-    else:
-        return 'i386'
+    for (pattern, arch) in cpu_table:
+        if _list_matches(cpuinfo, pattern):
+            return arch
+    return 'i386'
 
 
 def cpu_online_list():