disp: remove kernel mapping of writeback framebuffer

This change removes the fb_kmap debugfs node along with kernel
mapping of writeback framebuffer. It also replaces dma_buf_kmap
calls with dma_buf_vmap.

Change-Id: I2fbee7fa5922071f6805d8e6df540ce87056bc0b
Signed-off-by: Narendra Muppalla <NarendraM@codeaurora.org>

msm/msm_drv.h

@@ -1095,7 +1095,6 @@ void msm_gem_object_set_name(struct drm_gem_object *bo, const char *fmt, ...);
 
 int msm_gem_delayed_import(struct drm_gem_object *obj);
 
-void msm_framebuffer_set_kmap(struct drm_framebuffer *fb, bool enable);
 void msm_framebuffer_set_keepattrs(struct drm_framebuffer *fb, bool enable);
 int msm_framebuffer_prepare(struct drm_framebuffer *fb,
 		struct msm_gem_address_space *aspace);