ubi: fastmap: Add module parameter to control reserving filling pool PEBs

mainline inclusion
from mainline-v6.7-rc1
commit d4c48e5b58f12835de779f5425ef741c4d0fb53e
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I9195H
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d4c48e5b58f12835de779f5425ef741c4d0fb53e



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Adding 6th module parameter in 'mtd=xxx' to control whether or not
reserving PEBs for filling pool/wl_pool.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>