target/s390x: fix CSST decoding and runtime alignment check

target/s390x: fix CSST decoding and runtime alignment check

CSST is defined as:

    C(0xc802, CSST,    SSF,   CASS, la1, a2, 0, 0, csst, 0)

It means that the first parameter is handled by in1_la1().
in1_la1() fills addr1 field, and not in1.

Furthermore, when extract32() is used for the alignment check, the
third parameter should specify the number of trailing bits that must
be 0. For FC these numbers are:

    FC=0 (word, 4 bytes):        2
    FC=1 (double word, 8 bytes): 3
    FC=2 (quad word, 16 bytes):  4

For SC these numbers correspond to the size:

    SC=0: 0
    SC=1: 1
    SC=2: 2
    SC=3: 3
    SC=4: 4

Signed-off-by: Pavel Zbitskiy <pavel.zbitskiy@gmail.com>
Message-Id: <20180821025104.19604-4-pavel.zbitskiy@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>