MFC r325363:

MFC r325363:

Fix mpr(4) panics caused by bad drive mapping tables

sys/dev/mpr/mpr_mapping.c
	If _mapping_process_dpm_pg0 detects inconsistencies in the drive
	mapping table (stored in the HBA's NVRAM), abort reading it and
	continue to boot as if the mapping table were blank.  I observed
	such inconsistencies in several HBAs after upgrading firmware from
	14.0.0.0 to 15.0.0.0.

Reviewed by:	slm
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D12901

git-svn-id: svn://svn.freebsd.org/base/stable/10@326341 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f