dts: bindings: trivial clock bindings doc fixes

fix a typo in the "clock specifiers" discussion,
clarify that clock specifiers (the integer cells
part that goes with the phandle) may be empty

Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/clock/clock-bindings.txt

@@ -5,7 +5,7 @@ Sources of clock signal can be represented by any node in the device
 tree.  Those nodes are designated as clock providers.  Clock consumer
 nodes use a phandle and clock specifier pair to connect clock provider
 outputs to clock inputs.  Similar to the gpio specifiers, a clock
-specifier is an array of one more more cells identifying the clock
+specifier is an array of zero, one or more cells identifying the clock
 output on a device.  The length of a clock specifier is defined by the
 value of a #clock-cells property in the clock provider node.