dt-bindings: Fix JSON pointers

The correct syntax for JSON pointers begins with a '/' after the '#'.
Without a '/', the string should be interpreted as a subschema
identifier. The jsonschema module currently doesn't handle subschema
identifiers and incorrectly allows JSON pointers to begin without a '/'.
Let's fix this before it becomes a problem when jsonschema module is
fixed.

Converted with:
perl -p -i -e 's/yaml#definitions/yaml#\/definitions/g' `find Documentation/devicetree/bindings/ -name "*.yaml"`

Cc: Maxime Ripard <mripard@kernel.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: netdev@vger.kernel.org
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20201217223429.354283-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/iio/proximity/semtech,sx9310.yaml

@@ -72,7 +72,7 @@ properties:
       - finest
 
   semtech,startup-sensor:
-    $ref: /schemas/types.yaml#definitions/uint32
+    $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 1, 2, 3]
     default: 0
     description:
@@ -81,7 +81,7 @@ properties:
       compensation.
 
   semtech,proxraw-strength:
-    $ref: /schemas/types.yaml#definitions/uint32
+    $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 2, 4, 8]
     default: 2
     description:
@@ -89,7 +89,7 @@ properties:
       represent 1-1/N.
 
   semtech,avg-pos-strength:
-    $ref: /schemas/types.yaml#definitions/uint32
+    $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 16, 64, 128, 256, 512, 1024, 4294967295]
     default: 16
     description: