ext4: fix wrong unit use in ext4_mb_normalize_request

ext4: fix wrong unit use in ext4_mb_normalize_request

NRL_CHECK_SIZE will compare input req and size, so req and size should
be in same unit. Input req "fe_len" is in cluster unit while input
size "(8<<20)>>bsbits" is in block unit. Convert "fe_len" to block
unit to fix the mismatch.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20230603150327.3596033-2-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>