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/sde/sde_connector.h

@@ -408,7 +408,6 @@ struct sde_connector_dyn_hdr_metadata {
  * @blob_dither: Pointer to blob structure for default dither config
  * @blob_mode_info: Pointer to blob structure for mode info
  * @blob_panel_id: Pointer to blob structure for blob_panel_id
- * @fb_kmap: true if kernel mapping of framebuffer is requested
  * @event_table: Array of registered events
  * @event_lock: Lock object for event_table
  * @bl_device: backlight device node
@@ -465,7 +464,6 @@ struct sde_connector {
 	struct drm_property_blob *blob_mode_info;
 	struct drm_property_blob *blob_panel_id;
 
-	bool fb_kmap;
 	struct sde_connector_evt event_table[SDE_CONN_EVENT_COUNT];
 	spinlock_t event_lock;