Add an Intel StrataFlash (isf) driver FDT attachment.
Portions of the original changeset hooking up FDT use for BERI will be
merged separately.
Sponsored by: DARPA, AFRL
The driver attempts to support all documented parts, but has only been
tested with the 512Mbit part on the Terasic DE4 FPGA board. It should be
trivial to adapt the driver's attach routine to other embedded boards
using with any parts in the family.
Also import isfctl(8) which can be used to erase sections of the flash.
Sponsored by: DARPA, AFRL