`ArchPcode` doesn't return the right `ret_offset`

[DanielBotnik]

Description

from archinfo import ArchPcode
arch = ArchPcode("MIPS:LE:32:default")
print(arch.register_names[arch.ret_offset])
'f0'

While the result should be v0.

I think it because in the .cspec file, we can see that f0_1 comes before v0

<output>
        <pentry minsize="1" maxsize="8" metatype="float">
          <register name="f0_1"/>
        </pentry>
        <pentry minsize="1" maxsize="4">
          <register name="v0"/>
        </pentry>
		    <pentry minsize="5" maxsize="8">
          <addr space="join" piece1="v1" piece2="v0"/>
        </pentry>
</output>

I think a quick fix will be to select the tag that doesn't have metatype value, but I am not sure if its the right solution

Steps to reproduce the bug

No response

Environment

No response

Additional context

No response