porting/linux: Make BLE_NPL_TIME_FOREVER unsigned

There is no point in using singed value for this since ble_npl_mutex_pend takes uint32 as timeout parameter.

Author: sjanc

porting/npl/linux/include/nimble/nimble_npl_os.h

@@ -33,7 +33,7 @@ extern "C" {
 
 #define BLE_NPL_OS_ALIGNMENT (__WORDSIZE / 8)
 
-#define BLE_NPL_TIME_FOREVER INT32_MAX
+#define BLE_NPL_TIME_FOREVER UINT32_MAX
 
 struct ble_npl_eventq * ble_npl_eventq_dflt_get(void);
 void ble_npl_eventq_run(struct ble_npl_eventq *evq);