iio: use proper name for the R-Car SoC

It is 'R-Car', not 'RCar'. No code or binding changes, only descriptive text.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt

-* Renesas RCar GyroADC device driver
+* Renesas R-Car GyroADC device driver
 
 The GyroADC block is a reduced SPI block with up to 8 chipselect lines,
 which supports the SPI protocol of a selected few SPI ADCs. The SPI ADCs