disp: msm: remove unused sde debug function

Remove unused register debug function. DSI is now using a different
function instead and no longer needs this.

Change-Id: Ia0da4ba8447a162b4f327c34b26177bbaea0a0f9
Signed-off-by: Samantha Tran <samtran@codeaurora.org>

msm/sde_dbg.h

@@ -449,11 +449,6 @@ static inline void sde_dbg_reg_register_dump_range(const char *base_name,
 {
 }
 
-int sde_dbg_register_dsi_ctrl(void __iomem *base, const char *name)
-{
-	return 0;
-}
-
 static inline void sde_dbg_set_sde_top_offset(u32 blk_off)
 {
 }