SPL: Add XIP booting support

Enable support for XIP (execute in place) of U-Boot or kernel image. There is
no need to copy image from flash to ram if flash supports execute in place.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Reviewed-by: Alexandru Gagniuc <alex.g@adaptrum.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 732690c..4de8139 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -437,6 +437,15 @@
 	  a memory-mapped device makes it very easy to access. Loading from
 	  NOR is typically achieved with just a memcpy().
 
+config SPL_XIP_SUPPORT
+	bool "Support XIP"
+	depends on SPL
+	help
+	  Enable support for execute in place of U-Boot or kernel image. There
+	  is no need to copy image from flash to ram if flash supports execute
+	  in place. Its very useful in systems having enough flash but not
+	  enough ram to load the image.
+
 config SPL_ONENAND_SUPPORT
 	bool "Support OneNAND flash"
 	help