arm64: dts: exynos: Enable ir-spi in the TM2 and TM2E boards

Add the device tree node for the ir-spi driver which enables the
IR LED for remote controlling.

This patch sets first the GPR3[3] gpio line as a regulator-fixed
for enabling an external regulator which powers the IR LED.

Removes also the default assignment of GPG3[7] related to the
MOSI line of the SPI3 bus.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>