imx8qm: mek: enable dm-spl for pm

with u-boot,dm-spl added for imx8qm-pm node, and SPL_SIMPLE_BUS enabled,
the bind and probe code in board file could be removed.

Also we need to enlarge SYS_MALLOC_F_LEN to avoid calloc fail.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/imx8qm_mek_defconfig b/configs/imx8qm_mek_defconfig
index 747f3ea..9ec7676 100644
--- a/configs/imx8qm_mek_defconfig
+++ b/configs/imx8qm_mek_defconfig
@@ -7,7 +7,7 @@
 CONFIG_SPL_GPIO_SUPPORT=y
 CONFIG_SPL_LIBCOMMON_SUPPORT=y
 CONFIG_SPL_LIBGENERIC_SUPPORT=y
-CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_SYS_MALLOC_F_LEN=0x8000
 CONFIG_SPL_LOAD_IMX_CONTAINER=y
 CONFIG_IMX_CONTAINER_CFG="board/freescale/imx8qm_mek/uboot-container.cfg"
 CONFIG_TARGET_IMX8QM_MEK=y