Several years ago, the interrupt priority levels for devices were "flattened"
such that IPL_BIO, IPL_NET, and IPL_TTY (logical interrupt priority levels)
became aliases of IPL_VM (the logical interrupt priority level above which
memory allocation is not allowed). Unfortuantely, this meant that any
use of these logical interrupt priority levels to differentiate between
different interrupt service routines at the same auto-vectored interrupt
level was pointless... "when everyone is special, no one is".

Before this flattening happened, these distinct logical interrupt priority
levels levels were dynamically mapped to physical auto-vectored interrupt
levels based on which types of devices registered themselves at which auto-
vectored level. Now, splbio(), splnet(), etc. are all equivalent to splvm(),
which effectively blocks all device interrupts.

Switch to using the ISRPRI_* values provided by the common m68k interrupt
dispatch code, which allows interrupt handlers for devices that are more
latency-sensitive to be sorted earlier in the list of handlers at a given
auto-vectored interrupt level, as was originally intended.

Handle LED_DISK per DMA xfer.

branches: 1.7.20; 1.7.26; 1.7.28;
Normalize my licenses.

branches: 1.6.2; 1.6.4; 1.6.6;
Split softc/device_t for spc(4) and misc related cleanup.

branches: 1.5.74;
merge ktrace-lwp.

u_intNN_t -> uintNN_t

Use ANSI function decls, static, and const.

branches: 1.2.4;
TAB/space cleanup.

Switch hp300 to MI SCSI with MI mb89352 SPC SCSI driver (at last),
and remove old hp300 MD oscsi support derived from 4.4BSD-Lite2.