ASoC: SOF: Add clarifying comments for sof_core_debug and DSP dump flags

Update the comment for the global SOF level debug flags and add one for
the flags used to control the DSP dump functionality.

Document the expected behavior when the SOF_DBG_DUMP_OPTIONAL is passed
for the DSP dump:
Only print the dump if SOF_DBG_PRINT_ALL_DUMPS is set
Print must use KERN_DEBUG log level
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: NChao Song <chao.song@intel.com>
Reviewed-by: NKai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: NRanjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211223113628.18582-19-peter.ujfalusi@linux.intel.comSigned-off-by: NMark Brown <broonie@kernel.org>

sound/soc/sof/sof-priv.h

@@ -20,7 +20,7 @@
 #include <uapi/sound/sof/fw.h>
 #include <sound/sof/ext_manifest.h>
 
-/* debug flags */
+/* Flag definitions used in sof_core_debug (sof_debug module parameter) */
 #define SOF_DBG_ENABLE_TRACE	BIT(0)
 #define SOF_DBG_RETAIN_CTX	BIT(1)	/* prevent DSP D3 on FW exception */
 #define SOF_DBG_VERIFY_TPLG	BIT(2) /* verify topology during load */
@@ -35,11 +35,13 @@
 							*/
 #define SOF_DBG_PRINT_ALL_DUMPS		BIT(6) /* Print all ipc and dsp dumps */
 
+/* Flag definitions used for controlling the DSP dump behavior */
 #define SOF_DBG_DUMP_REGS		BIT(0)
 #define SOF_DBG_DUMP_MBOX		BIT(1)
 #define SOF_DBG_DUMP_TEXT		BIT(2)
 #define SOF_DBG_DUMP_PCI		BIT(3)
-#define SOF_DBG_DUMP_OPTIONAL		BIT(4) /* only dump if SOF_DBG_PRINT_ALL_DUMPS is set */
+/* Output this dump (at the DEBUG level) only when SOF_DBG_PRINT_ALL_DUMPS is set */
+#define SOF_DBG_DUMP_OPTIONAL		BIT(4)
 
 /* global debug state set by SOF_DBG_ flags */
 bool sof_debug_check_flag(int mask);