tests: boards: intel_adsp/smoke: fix abs() on unsigned value

Fix complier warning about using abs() with unsigned value.
So typecast it into signed 32-bit value first before feeding it
to abs(). The clock on DSP is not fast enough to need 64-bit
math for the extra one signed bit as 32-bit value.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

Author: dcpleung

tests/boards/intel_adsp/smoke/src/cpus.c

@@ -120,7 +120,7 @@ static void core_smoke(void *arg)
 	       clk_ratios[cpu] / 1000, clk_ratios[cpu] % 1000);
 
 	for (int i = 0; i < cpu; i++) {
-		int32_t diff = MAX(1, abs(clk_ratios[i] - clk_ratios[cpu]));
+		int32_t diff = MAX(1, abs((int32_t)(clk_ratios[i] - clk_ratios[cpu])));
 
 		zassert_true((clk_ratios[cpu] / diff) > 100,
 			     "clocks off by more than 1%%");

tests/boards/intel_adsp/smoke/src/main.c

@@ -36,7 +36,7 @@ ZTEST(intel_adsp, test_clock_calibrate)
 	printk("CLOCK: %lld Hz\n", (1000000ULL * (cyc1 - cyc0)) / host_dt);
 
 	/* Make sure we're within 1% of spec */
-	diff = abs(hz - CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC);
+	diff = abs((int32_t)(hz - CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC));
 	zassert_true((hz / MIN(1, diff)) > 100, "clock rate wrong");
 }