staging: android: Remove kernel-doc typo

Fix 'No description found for parameter 'prot_mask'' and 'Excess
struct/union/enum/typedef member 'prot_masks' description in
'ashmem_area'' warnings by removing typo
Signed-off-by: NCristina Moraru <cristina.moraru09@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ashmem.c

@@ -43,7 +43,7 @@
  * @unpinned_list:	The list of all ashmem areas
  * @file:		The shmem-based backing file
  * @size:		The size of the mapping, in bytes
- * @prot_masks:		The allowed protection bits, as vm_flags
+ * @prot_mask:		The allowed protection bits, as vm_flags
  *
  * The lifecycle of this structure is from our parent file's open() until
  * its release(). It is also protected by 'ashmem_mutex'