lib/mpi: fix spelling mistakes

Fix some spelling mistakes in comments:
flaged ==> flagged
bufer ==> buffer
multipler ==> multiplier
MULTIPLER ==> MULTIPLIER
leaset ==> least
chnage ==> change

Link: https://lkml.kernel.org/r/20210604074401.12198-1-thunder.leizhen@huawei.com


Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>