linux: Add ARM to CPU.type

Library/Homebrew/extend/os/linux/hardware/cpu.rb

@@ -12,6 +12,8 @@ module Hardware
       def type
         @type ||= if cpuinfo =~ /Intel|AMD/
           :intel
+        elsif cpuinfo =~ /ARM|Marvell/
+          :arm
         else
           :dunno
         end
@@ -71,7 +73,7 @@ module Hardware
       end
 
       def flags
-        @flags ||= cpuinfo[/^flags.*/, 0].split
+        @flags ||= cpuinfo[/^(flags|Features).*/, 0].split
       end
 
       # Compatibility with Mac method, which returns lowercase symbols