python: Remove 'is_ruby' function

This function is not used and should not be used. It does not really
make any sense.

Change-Id: I79ee7283ddbc282b9b803df33ad266b7a88a9c67
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50168
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>

src/python/gem5/coherence_protocol.py

@@ -42,24 +42,4 @@ class CoherenceProtocol(Enum):
     MOESI_AMD_BASE = 8
     MI_EXAMPLE = 9
     GPU_VIPER = 10
-    CHI = 11
-
-
-def is_ruby(protocol: CoherenceProtocol) -> bool:
-    """Specifies if a given protocol is Ruby or not
-
-    :returns: True if the given protocol is Ruby, otherwise false
-    """
-    ruby = (
-        CoherenceProtocol.MESI_THREE_LEVEL,
-        CoherenceProtocol.MESI_THREE_LEVEL_HTM,
-        CoherenceProtocol.ARM_MOESI_HAMMER,
-        CoherenceProtocol.GARNET_STANDALONE,
-        CoherenceProtocol.MESI_TWO_LEVEL,
-        CoherenceProtocol.MOESI_CMP_DIRECTORY,
-        CoherenceProtocol.MOESI_CMP_TOKEN,
-        CoherenceProtocol.MOESI_AMD_BASE,
-        CoherenceProtocol.GPU_VIPER,
-    )
-
-    return protocol in ruby
+    CHI = 11