arm: mvebu: Only set CONFIG_SKIP_LOWLEVEL_INIT for SPL

When running on the AXP I sometimes noticed a strange behavior. As some
characters are not echoed on the U-Boot prompt. Not disabling the
lowlevel_init code, especially calling cpu_init_cp15() in the main
U-Boot seems to solve this issue.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/include/configs/db-88f6820-gp.h b/include/configs/db-88f6820-gp.h
index 1dd4182..15f7bdf 100644
--- a/include/configs/db-88f6820-gp.h
+++ b/include/configs/db-88f6820-gp.h
@@ -16,7 +16,9 @@
 
 #define CONFIG_SYS_L2_PL310
 
+#ifdef CONFIG_SPL_BUILD
 #define CONFIG_SKIP_LOWLEVEL_INIT	/* disable board lowlevel_init */
+#endif
 #define CONFIG_SYS_GENERIC_BOARD
 #define CONFIG_DISPLAY_BOARDINFO_LATE