Is it OK to decrease MIPS3_TLB_WIRED_ENTRIES from 8 to 2?

I think the only mips3 port which uses wired TLB entry #2 to #7
is arc port. And arc port is going to make wired register dynamically
changeable. So, the value of MIPS3_TLB_WIRED_ENTRIES should be able to
be decreased to 2.

Also, I'd like to rename MIPS3_TLB_WIRED_ENTRIES to
MIPS3_TLB_WIRED_UPAGES as suggested by Urata-san.
Since the value of wired register becomes variable (on arc port),
and the value "2" only means number of wired TLB entries which
are used for UPAGES.

The only change in port independent (mips) part for this is:
  - change the definition of MIPS3_TLB_WIRED_ENTRIES from 8 to 2
  - rename MIPS3_TLB_WIRED_ENTRIES to MIPS3_TLB_WIRED_UPAGES
(patch is not included, since this is really trivial)

Is there any problem with this?
--
soda