They're both different cores:
* mips24k is an 8-stage pipeline, mips32r1 ABI, non-superscalar core.
* mips74k is a dual-issue 15-stage superscalar design, mips32r2 ABI.
They have different sets of quirks and bugs; these #define entries
will be used to work around these.
Now, strictly speaking, we should have CPU ABI families (mips32r1, mips32r2,
etc) and CPU core types (mips4k, mips24k, mips74k, etc.) But this is the
starting point of that particular tidy-up.
Reviewed by: imp@
Approved by: re@ (gjb)
57778cfec4