arch/x86/platform/mrst/mrst.c -- where __mrst_cpu_chip lives --

In your tree yes

is only built when CONFIG_X86_MRST is enabled.  You make it sound like
__mrst_cpu_chip needs to live any time that CONFIG_X86_INTEL_MID
is enabled, which sounds reasonable to me.

caveat:  given the current linux-next merge trees (as you mentioned).

Does anyone care?  If so, please help fix this muck.

It's already sorted, you are just seeing an out of order arrival of
patches to trees. I guess once kernel.org is back it'll all sort