xz: fix put_unaligned_{l,b}e32

Signed-off-by: Leonid Lisovskiy <lly.dev@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Sync code with busybox master fix
Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>
xz: support concatenated .xz streams

function                                             old     new   delta
xz_dec_reset                                           -      77     +77
unpack_xz_stream                                    2402    2397      -5

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>