markfiles/cargo-targets.inc.mk: Drop legacy triple

The legacy `riscv-none-embed` target triple is incorrect and the
toolchain using it has long been obsolete. With our CI no longer
using the obsolete toolchain, there is no need to handle that one
anymore.

makefiles/cargo-targets.inc.mk

@@ -37,7 +37,6 @@ $(CARGO_COMPILE_COMMANDS): $(BUILDDEPS)
 	        -e 's/"riscv64-none-elf"/"riscv32"/g' \
 	        -e 's/"riscv64-unknown-elf"/"riscv32"/g' \
 	        -e 's/"riscv64-elf"/"riscv32"/g' \
-	        -e 's/"riscv-none-embed"/"riscv32"/g' \
 	  | $(LAZYSPONGE) $@