linux-phytec-fsl

OMAPDSS: DPI: fix compilation if DSI not compiled in

Commit 100c826235793345efe06b3558cc9d36166b1e26 (OMAPDSS: DPI: use new
clock calculation code) breaks dpi.c compilation if DSI is not enabled
in the kernel configuration.

Fix compilation by adding dummy inline functions for the ones that dpi.c
references. The functions will never be called, as dpi.c knows that
there is no DSI device available.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>