imx: imx8m: not build bootaux when building SPL

No need to build bootaux in SPL stage

Signed-off-by: Peng Fan <peng.fan@nxp.com>

arch/arm/mach-imx/Makefile

@@ -10,7 +10,9 @@ obj-y	= iomux-v3.o
 endif
 
 ifeq ($(SOC),$(filter $(SOC),mx8m))
+ifneq ($(CONFIG_SPL_BUILD),y)
 obj-$(CONFIG_IMX_BOOTAUX) += imx_bootaux.o
+endif
 obj-$(CONFIG_ENV_IS_IN_MMC) += mmc_env.o
 obj-$(CONFIG_FEC_MAC_FUSE) += mac.o
 obj-$(CONFIG_SYS_I2C_MXC) += i2c-mxv7.o