arm64: dts: imx8mp-phyboard-pollux-rdk: correct eqos pad settings

BIT3 and BIT0 are reserved bits, should not touch.

Fixes: 6f968526 ("arm64: dts: freescale: Add support EQOS MAC on phyBOARD-Pollux-i.MX8MP")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>