Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with:		pfg
MFC After:		3 days
Sponsored by:		Netflix

BIO_READ and BIO_WRITE, we've handled this expanded syntax poorly in
drivers when the driver doesn't support a particular command.  Do a
sweep and fix that.

Reported by:	imp

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Rework the timeout code to use actual time rather than a DELAY() loop and
to use both typical and maximum to allow logging of timeout failures.
Also correct the erase timeout, it is specified in milliseconds not
microseconds like the other timeouts.  Do not invoke DELAY() between
status queries as this adds significant latency which in turn reduced
write performance substantially.

Sanity check timeout values from the hardware.

Implement support for buffered writes (only enabled on Intel/Sharp parts
for now).  This yields an order of magnitude speedup on the 64MB Intel
StrataFlash parts we use.

When making a copy of the block to modify, also keep a clean copy around
until we are ready to commit the block and use it to avoid unnecessary
erases.  In the non-buffer write case, also use it to avoid
unnecessary writes when the block has not been erased.  This yields a
significant speedup when doing things like zeroing a block.

Sponsored by:	DARPA, AFRL
Reviewed by:	imp (previous version)

d_getattr().  Since these drivers use disk(9) KPI and not directly GEOM, use
of that function means KPI layering violation, causing extra g_io_deliver()
call for the request.

Add support for partitioning CFI disks from FDT using geom_flashmap.

Sponsored by:	DARPA, AFRL

The flash commands and responses are little-endian and have to be
byte swapped on big-endian systems.  However the raw read of data
need not be swapped.

Make the cfi_read and cfi_write do the swapping, and provide a
cfi_read_raw which does not byte swap for reading data from
flash.