Use the existence of ATA Information VPD to determine if we should attempt
to query ATA functionality via ATA Pass-Through (16) as this page is defined
as "must" for SATL devices, hence indicating that the device is at least
likely to support Pass-Through (16).

This eliminates errors produced by CTL when ATA Pass-Through (16) fails.

Switch ATA probe daerror call to SF_NO_PRINT to avoid errors printing out
for devices which return invalid errors.

Output details about supported and choosen delete method when verbose booted.

Reviewed by:	mav
Approved by:	pjd (mentor)
MFC after:	 1 week
Suppress a GCC warning. This warning is actually bogus and newer GCC
versions than the one in base (dim@ mentioned he tried on 4.7.3 and 4.8.1)
do not whine about it, so, at some point this workaround will be reverted.

Reported by:	ache
Discussed with:	dim
Enable CAM SCSI to choice ATA TRIM during autodetection and correct method
names after increasing the priority of ATA TRIM.

Reviewed by:	mav
Approved by:	pjd (mentor)
MFC after:	1 week