befs: Convert befs_symlink_read_folio() to use folio_end_read()

befs: Convert befs_symlink_read_folio() to use folio_end_read()

This is slightly more efficient than separate calls to
folio_mark_uptodate() and folio_unlock(), and it's easier to read.
Get rid of the call to folio_set_error() as nobody will check this flag.

Cc: Luis de Bethencourt <luisbg@kernel.org>
Cc: Salah Triki <salah.triki@gmail.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240530202110.2653630-2-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>