[initcpiocfg] Refactor CPU-characteristics determination

The code is still over-wrought, but the API for cpuinfo
now exposes the interesting thing (is it Intel?) in
a useful -- more readable -- way.

src/modules/initcpiocfg/main.py

@@ -28,7 +28,29 @@ def pretty_name():
     return _("Configuring mkinitcpio.")
 
 
-def cpuinfo():
+class cpuinfo(object):
+    """
+    Object describing the current CPU's characteristics. It may be
+    be considered a named tuple, there's no behavior here.
+
+    Fields in the object:
+        - is_intel (if it's definitely an Intel CPU)
+        - is_amd (if it's definitely an AMD CPU)
+        - number_of_cores
+    It is possible for both is_* fields to be False.
+    """
+    def __init__(self):
+        self.is_intel = False
+        self.is_amd = False
+        self.number_of_cores = 0
+
+        cpu = self._cpuinfo()
+        self.is_intel = cpu['proc0']['vendor_id'].lower() == "genuineintel"
+        self.is_amd = cpu['proc0']['vendor_id'].lower() == "authenticamd"
+        self.number_of_cores = len(cpu)
+
+    @staticmethod
+    def _cpuinfo():
         """
         Return the information in /proc/cpuinfo as a dictionary in the following
         format:
@@ -172,10 +194,9 @@ def modify_mkinitcpio_conf(partitions, root_mount_point):
     else:
         hooks.extend(["filesystems"])
 
-    if btrfs == "yes" and cpu['proc0']['vendor_id'].lower() != "genuineintel":
+    if btrfs == "yes" and  not cpu.is_intel:
         modules.append("crc32c")
-    elif (btrfs == "yes"
+    elif (btrfs == "yes" and cpu.is_intel):
-          and cpu['proc0']['vendor_id'].lower() == "genuineintel"):
         modules.append("crc32c-intel")
     else:
         hooks.append("fsck")