lmb: Also remove __init from lmb_end_of_RAM() declaration in lmb.h

My previous patch (commit 4f8ee2c9: "lmb: Remove __init from
lmb_end_of_DRAM()") removed __init in lmb.c but missed the fact that it
was also marked as such in the .h

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>