all: update to LLVM 14

Switch over to LLVM 14 for static builds. Keep using LLVM 13 for regular
builds for now.

This uses a branch of the upstream Espressif branch to fix an issue,
see: https://github.com/espressif/llvm-project/pull/59

targets/esp32.json

@@ -1,6 +1,7 @@
 {
 	"inherits": ["xtensa"],
 	"cpu": "esp32",
+	"features": "+atomctl,+bool,+coprocessor,+debug,+density,+dfpaccel,+div32,+exception,+fp,+highpriinterrupts,+interrupt,+loop,+mac16,+memctl,+miscsr,+mul32,+mul32high,+nsa,+prid,+regprotect,+rvector,+s32c1i,+sext,+threadptr,+timerint,+windowed",
 	"build-tags": ["esp32", "esp"],
 	"scheduler": "tasks",
 	"serial": "uart",