Add EV-iMX280-NANO-X-MB board

A simple prototyping board with one microSD port, one Ethernet port,
2 USB ports, I2C, SPI, GPIO, and UART interfaces.

Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/board/out4/o4-imx6ull-nano/o4-imx6ull-nano.c b/board/out4/o4-imx6ull-nano/o4-imx6ull-nano.c
index fec1755..edb200e 100644
--- a/board/out4/o4-imx6ull-nano/o4-imx6ull-nano.c
+++ b/board/out4/o4-imx6ull-nano/o4-imx6ull-nano.c
@@ -39,16 +39,18 @@
 		if (ret)
 			return ret;
 
-		/*
-		 * Use 50M anatop loopback REF_CLK2 for ENET2,
-		 * clear gpr1[14], set gpr1[18].
-		 */
-		clrsetbits_le32(&iomuxc_regs->gpr[1], IOMUX_GPR1_FEC2_MASK,
-				IOMUX_GPR1_FEC2_CLOCK_MUX1_SEL_MASK);
+		if (!IS_ENABLED(CONFIG_EV_IMX280_NANO_X_MB)) {
+			/*
+			 * Use 50M anatop loopback REF_CLK2 for ENET2,
+			 * clear gpr1[14], set gpr1[18].
+			 */
+			clrsetbits_le32(&iomuxc_regs->gpr[1], IOMUX_GPR1_FEC2_MASK,
+					IOMUX_GPR1_FEC2_CLOCK_MUX1_SEL_MASK);
 
-		ret = enable_fec_anatop_clock(1, ENET_50MHZ);
-		if (ret)
-			return ret;
+			ret = enable_fec_anatop_clock(1, ENET_50MHZ);
+			if (ret)
+				return ret;
+		}
 
 		enable_enet_clk(1);
 	}