dmaengine: use proper name for the R-Car SoC

It is 'R-Car', not 'r-car'. No code or binding changes, only descriptive text.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

Documentation/devicetree/bindings/dma/shdma.txt

 * SHDMA Device Tree bindings
 
-Sh-/r-mobile and r-car systems often have multiple identical DMA controller
+Sh-/r-mobile and R-Car systems often have multiple identical DMA controller
 instances, capable of serving any of a common set of DMA slave devices, using
 the same configuration. To describe this topology we require all compatible
 SHDMA DT nodes to be placed under a DMA multiplexer node. All such compatible