kernel:config:mx6: boot time optimization

Disable CONFIG_EXPERT and CONFIG_DEBUG_KERNEL to reduce kernel boot time. With these options disabled, the system will boot about 10 seconds faster.

conf/machine/seco-mx6ull.conf

@@ -14,6 +14,10 @@ SUPPORTED_HARDWARE = " \
     NALLINO, \
 "
 
+EXTRA_IMAGEDEPENDS:append = " \
+    fngboot \
+"
+
 MACHINE_ESSENTIAL_EXTRA_RDEPENDS += " \
     kernel-module-imx6-spreadspectrum \
 "