LFU-362 cpu: imx8_cpu: fix the mpidr check

CID 22311217 (SolidRun#1 of 1): Operands don't affect result
(CONSTANT_EXPRESSION_RESULT) result_independent_of_operands:
plat->mpidr == 18446744073709551615UL /* (ulong)-1 */ is always false
regardless of the values of its operands. This occurs as the
logical operand of if.

The mpidr's type is u32, however dev_read_addr returns a value with type
fdt_addr_t(phys_addr_t) which is 64bit long. So the check never fail.

This patch we still keep mpidr as u32 type, because i.MX8 only has max
two cluster, the higher 32bit will always be 0. Use a variable addr
to do the check, if check pass, assign the lower 32 bit to plat->mpidr.

Reported-by: Coverity
Reviewed-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

drivers/cpu/imx8_cpu.c

@@ -215,19 +215,22 @@ static int imx8_cpu_probe(struct udevice *dev)
 {
 	struct cpu_imx_plat *plat = dev_get_plat(dev);
 	u32 cpurev;
+	fdt_addr_t addr;
 
 	set_core_data(dev);
 	cpurev = get_cpu_rev();
 	plat->cpurev = cpurev;
 	plat->rev = get_imx8_rev(cpurev & 0xFFF);
 	plat->type = get_imx8_type((cpurev & 0xFF000) >> 12);
 	plat->freq_mhz = imx8_get_cpu_rate(dev) / 1000000;
-	plat->mpidr = dev_read_addr(dev);
-	if (plat->mpidr == FDT_ADDR_T_NONE) {
+	addr = dev_read_addr(dev);
+	if (addr == FDT_ADDR_T_NONE) {
 		printf("%s: Failed to get CPU reg property\n", __func__);
 		return -EINVAL;
 	}
 
+	plat->mpidr = (u32)addr;
+
 	return 0;
 }