drm/vkms: Fix typo and preposion in function documentation

Fix typo in word 'blend' and in the word 'destination' and change
preposition 'at' to 'of' in function 'blend' documentation.
And change the task introduction word 'Todo' for the word all in uppercase
- 'TODO'. With the TODO word all in uppercase (as it's the standard) it's
easier to find the tasks that have to be done throughout the code.

Changes since V3:
 Rodrigo:
 - Merge the patch series into a single patch since it contains one single
 logical change

Changes since V2:
 - Add fix typo in  word 'destination'
 - Add change of the preposition
 - Fix the name of the function in log message
 - Add the change in word 'Todo'

Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Gabriela Bittencourt <gabrielabittencourt00@gmail.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191104161424.18105-1-gabrielabittencourt00@gmail.com

drivers/gpu/drm/vkms/vkms_composer.c

@@ -43,18 +43,18 @@ static uint32_t compute_crc(void *vaddr_out, struct vkms_composer *composer)
 }
 
 /**
- * blend - belnd value at vaddr_src with value at vaddr_dst
+ * blend - blend value at vaddr_src with value at vaddr_dst
  * @vaddr_dst: destination address
  * @vaddr_src: source address
  * @dest_composer: destination framebuffer's metadata
  * @src_composer: source framebuffer's metadata
  *
  * Blend value at vaddr_src with value at vaddr_dst.
- * Currently, this function write value at vaddr_src on value
+ * Currently, this function write value of vaddr_src on value
  * at vaddr_dst using buffer's metadata to locate the new values
- * from vaddr_src and their distenation at vaddr_dst.
+ * from vaddr_src and their destination at vaddr_dst.
  *
- * Todo: Use the alpha value to blend vaddr_src with vaddr_dst
+ * TODO: Use the alpha value to blend vaddr_src with vaddr_dst
  *	 instead of overwriting it.
  */
 static void blend(void *vaddr_dst, void *vaddr_src,