dt-bindings: i2c: i2c-sprd: convert to YAML

Convert the Spreadtrum SC9860 I2C controller bindings to DT schema.
Adjust filename to match compatible.

Signed-off-by: Stanislav Jakubek <stano.jakubek@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>