ubi: fastmap: Remove unneeded break condition while filling pools

mainline inclusion
from mainline-v6.7-rc1
commit 415e4723c4325464d489c1ef3335eb6679905471
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=415e4723c4325464d489c1ef3335eb6679905471



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Change pool filling stop condition. Commit d09e9a2b ("ubi:
fastmap: Fix high cpu usage of ubi_bgt by making sure wl_pool
not empty") reserves fastmap data PEBs after filling 1 PEB in
wl_pool. Now wait_free_pebs_for_pool() makes enough free PEBs
before filling pool, there will still be at least 1 PEB in pool
and 1 PEB in wl_pool after doing ubi_refill_pools().

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