Avoid undefined behaviour from shifting left into the sign bit:
hw/ide/ahci.c:551:36: runtime error: left shift of 255 by 24 places cannot be represented in type 'int'
(Unfortunately C's promotion rules mean that in the expression
"some_uint8_t_variable << 24" the LHS gets promoted to signed
int before shifting.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: John Snow <jsnow@redhat.com>