trace: add CONFIG_DISABLE_TRACE_PRINTK option

Poorly made kernel trees often use trace_printk() without
properly guarding them in a #ifdef macro.
Such usage of trace_printk() causes a warning at
boot and additional memory allocation.

This option serves to disable those all at once with ease.

Change-Id: I2cb2085f48064bda8c18806597c5aee57237dca6
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Signed-off-by: Alex Naidis <alex.naidis@linux.com>