Merge #1054

1054: riscv fixes r=lulf a=swolix

With these changes I can run embassy on our RISC-V processor, please consider merging this, feedback is very welcome.

I don't fully understand the code in the executor, but I have implemented a critical section by globally disabling interrupts, which means the wfi inside the critical section will hang the whole thing.

Co-authored-by: Sijmen Woutersen <sijmen.woutersen@gmail.com>

embassy-macros/Cargo.toml

@@ -23,6 +23,7 @@ proc-macro = true
 [features]
 std = []
 wasm = []
+riscv = []
 
 # Enabling this cause interrupt::take! to require embassy-executor
 rtos-trace-interrupt = []