lmb: Remove lmb_reserve_flags()

lmb: Remove lmb_reserve_flags()

lmb_reserve() is just calling lmb_reserve_flags() with LMB_NONE.
There's not much we gain from this abstraction.
So let's remove the latter, add the flags argument to lmb_reserve()
and make the code a bit easier to follow.

Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Tested-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>