NAND boot: MPC8313ERDB support

Note that with older board revisions, NAND boot may only work after a
power-on reset, and not after a warm reset.  I don't have a newer board
to test on; if you have a board with a 33MHz crystal, please let me know
if it works after a warm reset.

Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/lib_ppc/time.c b/lib_ppc/time.c
index 2649d5f..f093a57 100644
--- a/lib_ppc/time.c
+++ b/lib_ppc/time.c
@@ -67,7 +67,7 @@
 }
 
 /* ------------------------------------------------------------------------- */
-
+#ifndef CONFIG_NAND_SPL
 unsigned long ticks2usec(unsigned long ticks)
 {
 	ulong tbclk = get_tbclk();
@@ -83,7 +83,7 @@
 
 	return ((ulong)ticks);
 }
-
+#endif
 /* ------------------------------------------------------------------------- */
 
 int init_timebase (void)