Docs: Fixing spelling errors in Documentation/devicetree/bindings/

Revised patch fixing six spelling errors within
Documentation/devicetree/bindings/. "specfied" replaced with "specified"
in all three files modified. "atleast" seperated into "at least" three
times in samsung-pinctrl.txt. This should remove any confusion that a
reader might have.

Signed-off-by: Marlon Rac Cambasis <marlonrc08@gmail.com>
Link: https://lore.kernel.org/r/20201007071705.GA11381@marlonpc-debian
Signed-off-by: Rob Herring <robh@kernel.org>