OMAPDSS: Cleanup DSSDBG with dynamic pr_debug function

The printk in DSSDBG function definition is replaced with dynamic debug enabled
pr_debug(). The use of dynamic debugging provides more flexibility as each debug
statement can be enabled or disabled dynamically on basis of source filename,
line number, module name etc., by writing to a control file in debugfs
filesystem. For better understanding please refer to
Documentation/dynamic-debug-howto.txt.

The DSSDBGF() differs from DSSDBG() by providing function name. However,
function name, line number, module name and thread ID can be printed through
dynamic debug by setting appropriate flags 'f','l','m' and 't' in the debugfs
control file. So, DSSDBGF instances are replaced with DSSDBG.

Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Reviewed-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>