hw/scsi/vmw_pvscsi.c: Use device_cold_reset() to reset SCSI devices

hw/scsi/vmw_pvscsi.c: Use device_cold_reset() to reset SCSI devices

Currently the vwm_pvscsi controller resets individual SCSI devices
with the device_legacy_reset() function.  The only difference between
this and device_cold_reset() is that device_legacy_reset() resets the
device but not any child qbuses it might have.

In this case, no SCSI device has a child qbus, so the functions have
the same behaviour.  Switch to device_cold_reset() to move away from
using the deprecated function, and bring this SCSI controller in to
line with what all the others do.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20221013160623.1296109-3-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>