lantiq: ltq-tapi: fix compatibility with Linux 4.15+

Linux 4.15 removes the init_timer() API. It's replaced by two functions:
- timer_setup() is used instead of init_timer() and also replaces the
  timer "function" (callback) setup.
- from_timer() has to be used to obtain the use-case specific data from
  a struct timer_list, which is now passed to the timer callback.

Update the timer API to be compatible with Linux 4.15+ so it compiles
with the upcoming Linux 4.19 kernel update.

Signed-off-by: Martin Blumenstingl <[email protected]>

package/kernel/lantiq/ltq-tapi/patches/400-linux-415.patch

@@ -0,0 +1,48 @@
+--- a/src/drv_tapi_linux.c
++++ b/src/drv_tapi_linux.c
+@@ -119,7 +119,11 @@ struct _TAPI_FD_PRIV_DATA
+ /* ============================= */
+ /* Local Functions               */
+ /* ============================= */
++#if LINUX_VERSION_CODE < KERNEL_VERSION(4,15,0)
+ static IFX_void_t TAPI_timer_call_back (IFX_ulong_t arg);
++#else
++static IFX_void_t TAPI_timer_call_back (struct timer_list *t);
++#endif
+ #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20))
+ static IFX_void_t TAPI_tqueue (IFX_void_t *pWork);
+ #else /* for Kernel newer or equal 2.6.20 */
+@@ -3384,11 +3388,15 @@ Timer_ID TAPI_Create_Timer(TIMER_ENTRY p
+    pTimerData->nArgument = nArgument;
+    pTimerData->bStopped = IFX_FALSE;
+ 
++#if (LINUX_VERSION_CODE < KERNEL_VERSION(4,15,0))
+    init_timer(&(pTimerData->Timer_List));
+ 
+    /* set timer call back function */
+    pTimerData->Timer_List.function = TAPI_timer_call_back;
+    pTimerData->Timer_List.data = (IFX_ulong_t) pTimerData;
++#else
++   timer_setup(&(pTimerData->Timer_List), TAPI_timer_call_back, 0);
++#endif
+ 
+    /* Initialize Timer Task */
+ #ifdef LINUX_2_6
+@@ -3529,9 +3537,17 @@ static IFX_void_t TAPI_tqueue (struct wo
+ 
+    \param  arg          Pointer to corresponding timer ID.
+ */
++#if LINUX_VERSION_CODE < KERNEL_VERSION(4,15,0)
+ static IFX_void_t TAPI_timer_call_back (IFX_ulong_t arg)
++#else
++static IFX_void_t TAPI_timer_call_back (struct timer_list *t)
++#endif
+ {
++#if LINUX_VERSION_CODE < KERNEL_VERSION(4,15,0)
+    Timer_ID Timer = (Timer_ID) arg;
++#else
++   Timer_ID Timer = from_timer(Timer, t, Timer_List);
++#endif
+    /* do the operation in process context,
+       not in interrupt context */
+ #ifdef LINUX_2_6