linux-wandboard

MLK-16536-11 video: fbdev: dcss: add '__maybe_unused' to 'dtg_irq_mask()'

The function 'dtg_irq_mask()' is not used at this
moment which caused gcc compiler generate the build
warning:

"‘dtg_irq_mask’ defined but not used [-Wunused-function]"

So add attribute '__maybe_unused' to 'dtg_irq_mask()'
functon definition to avoid this build warning.

Signed-off-by: Fancy Fang <chen.fang@nxp.com>
Reviewed-by: Robby Cai <robby.cai@nxp.com>