mm/mmap: introduce vma_set_range()

There is a lot of code needs to set the range of vma in mmap.c, introduce
vma_set_range() to simplify the code.

Link: https://lkml.kernel.org/r/20240124035719.3685193-1-yajun.deng@linux.dev


Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>