power: qpnp-smbcharger: add PR_MISC as a debug_mask level

Deprecate some of the older and more spammy debug logs into a separate
PR_MISC debug_mask level to not interfere with normal debugging.

Also, add a PR_STATUS in the external_power_changed function for
whenever the USB current actually is changed. Deprecate the old one that
prints the USB current whenever a power supply changed is called into
the new PR_MISC category.

Change-Id: Ibfedd04b6f0ff706fde80449af173d8f92047790
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>