[brcmfmac] Rework dbg_hexdump

Reorganize hexdump functionality so that it:
- doesn't double-print when BRCMF_INFO_VAL is enabled
- prints addresses
- properly handles the header annotation
- prints 16 bytes/line
- Made all brcmf_hexdumps invocations conditional so that just enabling
  debug wouldn't cause logfile spew
- Removed hexdumps that were used for previous experiments but are no
  longer needed

Note that CONFIG_BRCMFMAC_DBG is enabled by default now, to make life
easier for us during debugging. No additional output will be generated,
but it means that only one variable (brcmf_msg_filter) needs to be set
to get log messages instead of two. There should be minimal impact on
performance since this pulls in a single conditional check.

WLAN-733

Test: Builds, smoke test with Netgear router. Verified that no messages
are produced with brcmf_msg_filter == 0 and reasonable spew is produced
with debug flags enabled (tried BRCMF_BYTES_VAL | BRCMF_DATA_VAL).

Change-Id: I3d15ad1f76da8584b496fea80c0a8c87ac84e67f
7 files changed