- Check the return value from sunxi_init_platform_r_twi().
- Print the PMIC banner before doing anything that might fail.
- Remove double prefixes in error messages.
- Consistently omit the trailing period.
- No need to print the unknown SoC's ID, since we already did that
  earlier in bl31_platform_setup().
- On the other hand, do print the ID of the unknown PMIC.
- Try to keep the messages concise, as the large string size in these
  files was causing the firmware to spill into the next page.
- Downgrade the banner from NOTICE to INFO. It's purely informational,
  and people should be using debug builds on untested hardware anyway.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Change-Id: Ib909408a5fdaebe05470fbce48d245dd0bf040eb