wlan: Added support to check the kernel version.

Added condtion to check the kernel version is greater than or equal
to the 4.14 for wpalUnRegisterInterrupt in vos_watchdog_wlan_shutdown
function.

Change-Id: I8da32966f5ed7773b56a3d3305adf6dae4126fe7
CRs-Fixed: 2785420
diff --git a/CORE/VOSS/src/vos_sched.c b/CORE/VOSS/src/vos_sched.c
index cccc647..d5ee1d5 100644
--- a/CORE/VOSS/src/vos_sched.c
+++ b/CORE/VOSS/src/vos_sched.c
@@ -2038,8 +2038,10 @@
        return VOS_STATUS_E_FAILURE;
     }
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,14,0))
     wpalUnRegisterInterrupt(DXE_INTERRUPT_RX_READY);
     wpalUnRegisterInterrupt(DXE_INTERRUPT_TX_COMPLE);
+#endif
 
     /* Take the lock here */
     spin_lock(&gpVosWatchdogContext->wdLock);