[SCSI] megaraid: fix warnings when CONFIG_PROC_FS=n

drivers/scsi/megaraid.c: In function 'megaraid_probe_one':
drivers/scsi/megaraid.c:4893: warning: implicit declaration of function 'mega_create_proc_entry'
drivers/scsi/megaraid.c: In function 'megaraid_remove_one':
drivers/scsi/megaraid.c:4968: warning: unused variable 'buf'

Fix by adding #defines

Signed-off-by: walter harms <wharms@bfs.de>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>