include/configs: ls1012a: add pfe stop command

This adds pfe stop command before boot linux kernel
to fix a problem that ethernet won't be workable
after enter linux. Because there is a h/w limitation
in LS1012A PFE, to re-initialize PFE it has to be
safe shutdown, these steps are done through PFE stop.

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/include/configs/ls1012afrdm.h b/include/configs/ls1012afrdm.h
index 8c7d4e5..8a3ebf0 100644
--- a/include/configs/ls1012afrdm.h
+++ b/include/configs/ls1012afrdm.h
@@ -60,7 +60,7 @@
 	"installer=load usb 0:2 $load_addr "	\
 		   "/flex_installer_arm64.itb; "	\
 		   "bootm $load_addr#$board\0"	\
-	"qspi_bootcmd=echo Trying load from qspi..;"	\
+	"qspi_bootcmd=pfe stop; echo Trying load from qspi..;"	\
 		"sf probe && sf read $load_addr "	\
 		"$kernel_addr $kernel_size && bootm $load_addr#$board\0"