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: Cristina Moraru <cristina.moraru09@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>