hw/mips: Declare all length properties as unsigned

hw/mips: Declare all length properties as unsigned

Some length properties are signed, other unsigned:

  hw/mips/cps.c:183:    DEFINE_PROP_UINT32("num-vp", MIPSCPSState, num_vp, 1),
  hw/mips/cps.c:184:    DEFINE_PROP_UINT32("num-irq", MIPSCPSState, num_irq, 256),
  hw/misc/mips_cmgcr.c:215:    DEFINE_PROP_INT32("num-vp", MIPSGCRState, num_vps, 1),
  hw/misc/mips_cpc.c:167:    DEFINE_PROP_UINT32("num-vp", MIPSCPCState, num_vp, 0x1),
  hw/misc/mips_itu.c:552:    DEFINE_PROP_INT32("num-fifo", MIPSITUState, num_fifo,
  hw/misc/mips_itu.c:554:    DEFINE_PROP_INT32("num-semaphores", MIPSITUState,

Since negative values are not used (the minimum is '0'),
unify by declaring all properties as unsigned.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230203113650.78146-9-philmd@linaro.org>