cgtqmx6eval: Fix unused variable warning

The variable usdhc2_pads is only referenced during SPL builds, add a guard.

Cc: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/congatec/cgtqmx6eval/cgtqmx6eval.c b/board/congatec/cgtqmx6eval/cgtqmx6eval.c
index a4a6029..24956a8 100644
--- a/board/congatec/cgtqmx6eval/cgtqmx6eval.c
+++ b/board/congatec/cgtqmx6eval/cgtqmx6eval.c
@@ -71,6 +71,7 @@
 	IOMUX_PADS(PAD_EIM_D27__UART2_RX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL)),
 };
 
+#ifndef CONFIG_SPL_BUILD
 static iomux_v3_cfg_t const usdhc2_pads[] = {
 	IOMUX_PADS(PAD_SD2_CLK__SD2_CLK   | MUX_PAD_CTRL(USDHC_PAD_CTRL)),
 	IOMUX_PADS(PAD_SD2_CMD__SD2_CMD   | MUX_PAD_CTRL(USDHC_PAD_CTRL)),
@@ -94,6 +95,7 @@
 	IOMUX_PADS(PAD_SD3_DAT7__SD3_DATA7 | MUX_PAD_CTRL(USDHC_PAD_CTRL)),
 	IOMUX_PADS(PAD_SD3_RST__SD3_RESET | MUX_PAD_CTRL(USDHC_PAD_CTRL)),
 };
+#endif
 
 static iomux_v3_cfg_t const usdhc4_pads[] = {
 	IOMUX_PADS(PAD_SD4_CLK__SD4_CLK   | MUX_PAD_CTRL(USDHC_PAD_CTRL)),