DRIVERS: Fix compile warnings in video drivers

This fixs the warnings below when earlysuspend is not enabled and drops unused code from msm_lcdc.c

- drivers/video/msm/msm_fb.c:39:13: warning: 'msmfb_resume_handler' declared 'static' but never defined [-Wunused-function]
   static void msmfb_resume_handler(struct early_suspend *h);
               ^
- drivers/video/msm/msm_fb.c:40:13: warning: 'msmfb_resume' declared 'static' but never defined [-Wunused-function]
   static void msmfb_resume(struct work_struct *work);
               ^
- drivers/video/msm/msm_fb.c:86:17: warning: 'mdpclk_on' defined but not used [-Wunused-variable]
   static atomic_t mdpclk_on = ATOMIC_INIT(1);
                   ^
- drivers/video/msm/mdp_lcdc.c:484:11: warning: unused variable 'dma2_cfg' [-Wunused-variable]
   uint32_t dma2_cfg;
            ^
- drivers/video/msm/mdp_lcdc.c:483:19: warning: unused variable 'mdp' [-Wunused-variable]
   struct mdp_info *mdp = lcdc->mdp;
                    ^