block: first step of splitting ll_rw_blk, rename it

Then we retain history in blk-core.c
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

block/Makefile

@@ -2,7 +2,7 @@
 # Makefile for the kernel block layer
 #
 
-obj-$(CONFIG_BLOCK) := elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o
+obj-$(CONFIG_BLOCK) := elevator.o blk-core.o ioctl.o genhd.o scsi_ioctl.o
 
 obj-$(CONFIG_BLK_DEV_BSG)	+= bsg.o
 obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o