ext4: explicitly exit when ext4_find_inline_entry returns an error

ext4: explicitly exit when ext4_find_inline_entry returns an error

__ext4_find_entry currently ignores the return of ext4_find_inline_entry,
except for returning the bh or NULL when has_inline_data is 1.

Even though has_inline_data is set to 1 before calling
ext4_find_inline_entry and would only be set to 0 when that function
returns NULL, check for an encoded error return explicitly in order to
exit.

That makes the code more readable, not requiring that one assumes the cases
when has_inline_data is 1.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Link: https://patch.msgid.link/20240821152324.3621860-4-cascardo@igalia.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>