Revision 285679

Add support for two workarounds for known issues booting GPT in legacy mode on some hardware

For Lenovo laptops with buggy bios (x220, t420, t520):
	Write the 0xee entry into the second slot in the pmbr instead of the first

For some Dell and HP models:
	The BIOS gives a warning message when booting in legacy mode from a GPT partitioned disk where the 0xee partition in the pmbr is not flagged active
	For models known to have this problem, mark the pmbr active during installation

Use smbios data to identify machines known to be affected by any of the above, and offer the user the option to apply the workaround

In bsdinstall's ufs auto mode (autopart partition wizard):
	Allow users to select which type of partition table to use
	Keep current defaults: MBR for BIOS, GPT for UEFI
	This allows users to choose GPT for legacy boot if they wish

PR:		184910
PR:		194359
Reviewed by:	Michael Dexter
Approved by:	marcel
MFC after:	3 days
X-MFC-With:	r285594
Relnotes:	yes
Sponsored by:	ScaleEngine Inc.
Differential Revision:	https://reviews.freebsd.org/D3091