target-ppc: Store Quadword Conditional Drops Size Bit

target-ppc: Store Quadword Conditional Drops Size Bit

The size and register information are encoded into the reserve_info field
of CPU state in the store conditional translation code.  Specifically, the
size is shifted left by 5 bits (see target-ppc/translate.c gen_conditional_store).

The user-mode store conditional code erroneously extracts the size by ANDing
with a 4 bit mask; this breaks if size >= 16.

Eliminate the mask to make the extraction of size mirror its encoding.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>