trivial: Miscellaneous documentation typo fixes

Documentation/DMA-API.txt

Documentation/RCU/rculist_nulls.txt

Documentation/SM501.txt

Documentation/block/deadline-iosched.txt

Documentation/braille-console.txt

Documentation/driver-model/devres.txt

Documentation/edac.txt

Documentation/fb/sh7760fb.txt

Documentation/filesystems/autofs4-mount-control.txt

Documentation/filesystems/caching/netfs-api.txt

Documentation/filesystems/ext4.txt

Documentation/filesystems/fiemap.txt

Documentation/filesystems/nfs-rdma.txt

Documentation/filesystems/proc.txt

Documentation/filesystems/sysfs-pci.txt

Documentation/filesystems/vfat.txt

Documentation/gpio.txt

Documentation/kdump/kdump.txt

Documentation/kernel-parameters.txt

Documentation/kobject.txt