`msg.h` needs `ipc/trace.h` for `sof_ipc_dma_trace_posn`
Fixes commit b91e253f65 ("include: sof: debug: Split panic.h into
Zephyr and XTOS-specific headers") that broke `scripts/fuzz.sh` because
it stopped `ipc/msg.h` from accidentally getting `ipc/trace.h` through
`panic.h`.
Fixes:
```
src/include/sof/ipc/msg.h:146:34: warning: declaration of
'struct sof_ipc_dma_trace_posn' will not be visible outside
of this function [-Wvisibility]
void ipc_build_trace_posn(struct sof_ipc_dma_trace_posn *posn);
```
```
sof/src/trace/dma-trace.c:160:23: warning: incompatible pointer
types passing 'struct sof_ipc_dma_trace_posn *' to parameter of
type 'struct sof_ipc_dma_trace_posn *' [-Wincompatible-pointer-types]
ipc_build_trace_posn(&sof->dmat->posn);
^~~~~~~~~~~~~~~~
sof/zephyr/../src/include/sof/ipc/msg.h:146:58: note: passing argument
to parameter 'posn' here
void ipc_build_trace_posn(struct sof_ipc_dma_trace_posn *posn);
```
Signed-off-by: Marc Herbert <marc.herbert@intel.com>