ll_rw_block() funcation has been removed

[Lukas Czerner]

Hi,

ll_rw_block() has been removed with commit 79f597842069 ("fs/buffer:
remove ll_rw_block() helper"), but I noticed that it's still beeing
referenced in drivers/misc/lkdtm/core.c. I know nothing about LKDTM so I
can't even tell whether it's a problem at all, but I though it's worth
letting you know.

Best regards,
-Lukas