docs: Remove outdated README

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

doc/README.md

diff --git a/doc/README.md b/doc/README.md
deleted file mode 100644
index b8da532..0000000
--- a/doc/README.md
+++ /dev/null
@@ -1,7 +0,0 @@
-# Available flash commands
-
-- `cargo rriscv32imac`/`cargo rrv32imac`: Use the `riscv32imac-unknown-none-elf` target
-- `cargo rriscv32imc`/`cargo rrv32imc`: Use the `riscv32imc-unknown-none-elf` target
-- `cargo rthumbv7em`/`cargo rtv7em`: Use the `thumbv7em-none-eabi` target
-
-Before flashing, write your board name to the environment variable `PLATFORM` or to a file named `platform`