lcd: Add CONFIG_LCD_ALIGNMENT to select frame buffer alignment

The normal alignment is PAGE_SIZE, but if this is defined, we can support
other alignments.

The motivation for this change is to make the display section-aligned on
ARM so that we can easily turn off data caching for the frame buffer region
without resorting to level 2 page tables.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/README b/README
index afdf591..5c03be7 100644
--- a/README
+++ b/README
@@ -1469,6 +1469,16 @@
 		Normally display is black on white background; define
 		CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
 
+
+		CONFIG_LCD_ALIGNMENT
+
+		Normally the LCD is page-aligned (tyically 4KB). If this is
+		defined then the LCD will be aligned to this value instead.
+		For ARM it is sometimes useful to use MMU_SECTION_SIZE
+		here, since it is cheaper to change data cache settings on
+		a per-section basis.
+
+
 - Splash Screen Support: CONFIG_SPLASH_SCREEN
 
 		If this option is set, the environment is checked for