erofs: fold in z_erofs_reload_indexes()

The name of this function looks not very accurate compared to it's
implementation and it's only a wrapper to erofs_read_metabuf(). So,
let's fold it directly instead.

Signed-off-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220927032518.25266-1-zbestahu@gmail.com


Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>