Update no_atomic.rs

Author: taiki-e

no_atomic.rs

@@ -7,6 +7,7 @@ const NO_ATOMIC_CAS: &[&str] = &[
     "bpfel-unknown-none",
     "msp430-none-elf",
     "riscv32i-unknown-none-elf",
+    "riscv32im-unknown-none-elf",
     "riscv32imc-unknown-none-elf",
     "thumbv4t-none-eabi",
     "thumbv6m-none-eabi",
@@ -49,6 +50,7 @@ const NO_ATOMIC_64: &[&str] = &[
     "riscv32gc-unknown-linux-gnu",
     "riscv32gc-unknown-linux-musl",
     "riscv32i-unknown-none-elf",
+    "riscv32im-unknown-none-elf",
     "riscv32imac-unknown-none-elf",
     "riscv32imc-unknown-none-elf",
     "thumbv4t-none-eabi",
@@ -66,5 +68,6 @@ const NO_ATOMIC: &[&str] = &[
     "avr-unknown-gnu-atmega328",
     "msp430-none-elf",
     "riscv32i-unknown-none-elf",
+    "riscv32im-unknown-none-elf",
     "riscv32imc-unknown-none-elf",
 ];