Fix GRALLOC_USAGE_SW_WRITE flag documentation

Change-Id: Ie553c521290358bf37c6954f65f790162aa43730
Signed-off-by: Greg Hackmann <ghackmann@google.com>
diff --git a/include/hardware/gralloc.h b/include/hardware/gralloc.h
index 7c819f0..a6d9c1f 100644
--- a/include/hardware/gralloc.h
+++ b/include/hardware/gralloc.h
@@ -57,9 +57,9 @@
     
     /* buffer is never written in software */
     GRALLOC_USAGE_SW_WRITE_NEVER        = 0x00000000,
-    /* buffer is never written in software */
+    /* buffer is rarely written in software */
     GRALLOC_USAGE_SW_WRITE_RARELY       = 0x00000020,
-    /* buffer is never written in software */
+    /* buffer is often written in software */
     GRALLOC_USAGE_SW_WRITE_OFTEN        = 0x00000030,
     /* mask for the software write values */
     GRALLOC_USAGE_SW_WRITE_MASK         = 0x000000F0,