Since writing an SD card image generation script, the bootloader
needed to be altered to access individual binaries from specific
partitions. A new file, gpt.c with it's header gpt.h, have been added
to the bootloader to facilitate this.
The SDC has been added to the device tree for the VCU108
board. Additionally the SDC interrupt signal was added to the PLIC
node in the device tree. The PLIC itself was modified to accept the
SDC interrupt signal.
Rewrote copyflash to take advantage of the new peripheral. The new
peripheral has the neat ability to use CMD18 in the SD card
specification, allowing us to load multiple blocks in succession,
ending the chain of CMD18 commands with a CMD17.
