Linux Makefile, Readme, flash-sd.sh fix, and probe script

Created by: JacobPease

• Added a Makefile to the Linux directory to take care of the Buildroot setup and other dependencies.
• Linux makefile now copies the package contents with the correct package source.
• Removed duplicate line in Makefile.
• Buildroot can now be set up with the new Linux Makefile. The driver can now also be loaded from addins/vivado-risc-v and should be removed from the main Wally repo. A sed command customizes the package source location for the new buildroot directory.
• Adjusted the new makefile.
• Updated linux config. Works in QEMU now.
• Added device tree generation to Linux directory Makefile. Exits on not finding output/images folder in buildroot directory.
• Makefile dynamically generates all device tree files now.
• flash-sd.sh fixed. GPT table is now destroyed before re-partioning, thus avoiding backup table collisions.
• Created dependency tree for patch target in the linux subdirectory Makefile.
• Fixed Makefile bugs, and removed old code.
• Stopped makefile from crashing when patch is already applied.
• Fixed device tree generation make rule. Make targets are simplified.
• Fixed bugs. Added an 'all' target that performs the whole process of building the images needed for booting linux, including device tree files.
• Added a README.md for the linux directory. WIP.
• Added details to the README.md for linux.
• Added instructions on disassembly to the README for Linux.
• Added a table of contents to the linux readme.
• Cleaned up some things.
• Added probe script to generate a single probe for the fpga.
• Fixed bug caused by errant tab size in probe script.