fsl: layerscape: guard *env_sf_get_env_addr() on CONFIG_ENV_IS_IN_SPI_FLASH

These functions can only be built and used when we have
ENV_IS_IN_SPI_FLASH, use that as a guard.

Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/freescale/ls1046aqds/ls1046aqds.c b/board/freescale/ls1046aqds/ls1046aqds.c
index 6a51dcd..aac5d9a 100644
--- a/board/freescale/ls1046aqds/ls1046aqds.c
+++ b/board/freescale/ls1046aqds/ls1046aqds.c
@@ -482,7 +482,7 @@
 	return (((val) >> 8) & 0x00ff) | (((val) << 8) & 0xff00);
 }
 
-#ifdef CONFIG_TFABOOT
+#if defined(CONFIG_TFABOOT) && defined(CONFIG_ENV_IS_IN_SPI_FLASH)
 void *env_sf_get_env_addr(void)
 {
 	return (void *)(CONFIG_SYS_FSL_QSPI_BASE + CONFIG_ENV_OFFSET);