mke2fs: Use unix_discard() for discards

There is generic discard function in struct_io_manager, or in
unix_io_manager to be specific. So use this instead of
mke2fs_discard_blocks().

Since mke2fs_discard_blocks() is not used anymore (and should not be)
remove it.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed