s/sharable/shareable in comments and documentation.

Statically-initialize the '851 / '030 protorp with MMU51_SRP_BITS. In
pmap_init(), re-initialize protorp with MMU51_CRP_BITS. Remove the now-
redundant code that does this in each of the m68k platforms.

Remove duplicated / slightly-tweaked loadustp() (load user segment table)
routines from all of the m68k ports using the shared pmap. Instead, in
pmap_init(), set up a function pointer to the appropriate mmu_load_urp*()
function in mmu_subr.s.

Add new headers that describe the 68851 (and 68030) MMU and
68040 (and 68060) MMU structures using names that more closely
align with Motorola's documentation.

The definitions here automagically adapt to 4K or 8K pages, based
on the value of PGSHIFT, which must be a compile-time constant.

Statically-initialize the '851 / '030 protorp with MMU51_SRP_BITS. In
pmap_init(), re-initialize protorp with MMU51_CRP_BITS. Remove the now-
redundant code that does this in each of the m68k platforms.

Remove duplicated / slightly-tweaked loadustp() (load user segment table)
routines from all of the m68k ports using the shared pmap. Instead, in
pmap_init(), set up a function pointer to the appropriate mmu_load_urp*()
function in mmu_subr.s.

Add new headers that describe the 68851 (and 68030) MMU and
68040 (and 68060) MMU structures using names that more closely
align with Motorola's documentation.

The definitions here automagically adapt to 4K or 8K pages, based
on the value of PGSHIFT, which must be a compile-time constant.

Add new headers that describe the 68851 (and 68030) MMU and
68040 (and 68060) MMU structures using names that more closely
align with Motorola's documentation.

The definitions here automagically adapt to 4K or 8K pages, based
on the value of PGSHIFT, which must be a compile-time constant.