add armv8m.main_soft_nofp_unaligned as a supporter clang runtime (for 20.1.0) (#2542)

Author: kilograham

cmake/preload/toolchains/pico_arm_cortex_m33_clang.cmake

@@ -1,7 +1,7 @@
 set(CMAKE_SYSTEM_PROCESSOR cortex-m33)
 
 # these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc) and under llvm_libc
-set(PICO_CLANG_RUNTIMES armv8m.main_soft_nofp armv8m.main-unknown-none-eabi)
+set(PICO_CLANG_RUNTIMES armv8m.main_soft_nofp armv8m.main_soft_nofp_unaligned armv8m.main-unknown-none-eabi)
 
 set(PICO_COMMON_LANG_FLAGS "-mcpu=cortex-m33 --target=armv8m.main-none-eabi -mfloat-abi=softfp -march=armv8m.main+fp+dsp")
 set(PICO_DISASM_OBJDUMP_ARGS --mcpu=cortex-m33 --arch=armv8m.main+fp+dsp)