Fix warning

using integer absolute value function 'abs' when argument is of floating
point type [-Werror,-Wabsolute-value]

Signed-off-by: Tom Hughes <tomtheengineer@gmail.com>

test/src/unit_test_common.c

@@ -78,7 +78,7 @@ void FILL_FLOAT_ARRAY_LIMIT_GT1 (ne10_float32_t *arr, ne10_uint32_t count)
 // this function checks whether the difference between two ne10_float32_t values is within the acceptable error range
 ne10_int32_t EQUALS_FLOAT (ne10_float32_t fa, ne10_float32_t fb , ne10_uint32_t err)
 {   ne10_float32_t tolerance = (ne10_float32_t)err / 200000;
-    if (abs(fa-fb) <= tolerance)
+    if (fabs(fa-fb) <= tolerance)
     {
         return 1;
     }