ARM: davinci: da850 board: change pr_warning() to pr_warn()

Change all pr_warning() calls to pr_warn(), as advised by checkpatch.pl.

Also, while modifying those pr_warning() calls change hardcoded
function names to use '"%s:", __func__' instead, and converted acronym
usage to upper case.

Signed-off-by: Robert Tivy <rtivy@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>