freescale: Ensure common commands are not included in SPL binary

Both the "qixis_reset" and esbc_validate" commands can only be used in
full U-Boot so do not build them in SPL.  As part of this rework the
qixis code to declare things as static and make use of __weak for
function aliases.

Cc; York Sun <york.sun@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/common/cmd_esbc_validate.c b/board/freescale/common/cmd_esbc_validate.c
index b3e5f01..f45e224 100644
--- a/board/freescale/common/cmd_esbc_validate.c
+++ b/board/freescale/common/cmd_esbc_validate.c
@@ -23,6 +23,7 @@
 	return 0;
 }
 
+#ifndef CONFIG_SPL_BUILD
 static int do_esbc_validate(cmd_tbl_t *cmdtp, int flag, int argc,
 				char * const argv[])
 {
@@ -82,3 +83,4 @@
 	"Put the core in spin loop (Secure Boot Only)",
 	""
 );
+#endif