LU-2335 kernel: add CONFIG_ prefix to config values

LU-2335 kernel: add CONFIG_ prefix to config values

Kernel uses CONFIG_ prefix for all values that comes from
Kconfig. So do the same for Lustre.

Rename OBD_MAX_IOCTL_BUFFER to CONFIG_LUSTRE_OBD_MAX_IOCTL_BUFFER,
LNET_MAX_PAYLOAD to CONFIG_LNET_MAX_PAYLOAD, and INVARIANT_CHECK
to CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK.

Signed-off-by: Peng Tao <tao.peng@emc.com>
Change-Id: I3b1fdea02ba195ce7ff0793c218ac1f505243bb3
Reviewed-on: http://review.whamcloud.com/4646
Tested-by: Hudson
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>