mips24k (and others?) no longer works

[Adrian Chadd]

hiya,

freebsd-head no longer boots on mips24k.

* COP1_UNUSABLE - turns out ruslan enabled COP1_UNUSABLE; but we are
always enabling it. We should conditionally enable it. I've disabled
setting the COP1 flag and now I don't get that error.
* ADDRESS_SPACE_ERR - not sure why yet; maybe this is (more) TLS change related:

ADDRESS_SPACE_ERR: pid 1 tid 100001 (init), uid 0: pc 0x41dd28 got a
read fault (type 0x4) at 0xffffffffffff8279
Trapframe Register Dump:
    zero: 0    at: 0    v0: 0    v1: 0x1
    a0: 0x50    a1: 0x1    a2: 0    a3: 0x1
    t0: 0x1    t1: 0x4cf000    t2: 0x40    t3: 0x1
    t4: 0    t5: 0    t6: 0    t7: 0
    t8: 0    t9: 0x41dd08    s0: 0x50    s1: 0x2
    s2: 0    s3: 0x1    s4: 0    s5: 0
    s6: 0    s7: 0    k0: 0    k1: 0
    gp: 0x1    sp: 0x7ffeedc8    s8: 0    ra: 0x41ea4c
    sr: 0xfc13    mullo: 0    mulhi: 0    badvaddr: 0xffffffffffff8279
    cause: 0x10    pc: 0x41dd28
Page table info for pc address 0x41dd28: pde = 0x809a8000, pte = 0xa001b91a
Dumping 4 words starting at pc address 0x41dd28:
8f828278 a04362c8 8f998410 2739c730



-adrian