remove all status checks. only handle release.

the release variable is all we need, turning a target on
or off for a given release.

the status checks were prone to bugs, and unnecessary; it
also broke certain benchmark scripts.

it's better to keep the lbmk logic simpler. board status
will be moved to the documentation instead.

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/coreboot/dell9020mt-nri_12mb/target.cfg

@@ -5,4 +5,3 @@ payload_seabios_withgrub="y"
 payload_seabios_grubonly="y"
 payload_memtest="y"
 grub_scan_disk="ahci"
-status="stable"

config/coreboot/dell9020mt-nri_12mb/warn.txt

@@ -1 +0,0 @@
-Completely stable with graphics, but IOMMU disabled by default; graphics cards only work with IOMMU turned off. Intel graphics works fine with IOMMU turned on. IOMMU is needed for Qubes to work properly. To turn on IOMMU, do this to your ROM before flashing (ONLY do this if using Intel graphics): ./nvramtool -C libreboot.rom -w iommu=Enable