mfd: Replace twl-* pr_ macros by the dev_ equivalent and do various cleanups

Since a structure device is available now, use the dev_ macros instead
of the pr_ ones.

Clean some badly formatted comments.
Remove some unused variables.
Move some variable to the place they belong.
Clean some badly wrapped lines.
Align variable definition
Add missing braces in if-then-else block.
Add blank line for better readability.
Move stuff here and there...

Conflicts:

	drivers/mfd/twl-core.c

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>