ia64: replace setup_irq() by request_irq()

request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

Changing 'ia64_native_register_percpu_irq' decleration to include
'irq_handler_t' as an argument type in arch/ia64/include/asm/hw_irq.h
was causing build error - 'unknown type name 'irq_handler_t''

This was due to below header file sequence,
+ include/interrupt.h
 + include/hardirq.h
  + asm/hardirq.h
   + include/irq.h
    + asm/hw_irq.h
       [ 'ia64_native_register_percpu_irq' declared w/ 'irq_handler_t']
 [ 'irq_handler_t' typedef'ed here in 'include/interrupt.h']

'register_percpu_irq' defined to 'ia64_native_register_percpu_irq' is
the one invoked by the caller, not the latter directly. This was done
to support paravirtualization which was removed around 4 years back.
And 'register_percpu_irq' is invoked only inside 'arch/ia64/kernel'.

So 'register_percpu_irq' define to 'ia64_native_register_percpu_irq' is
removed, instead 'ia64_native_register_percpu_irq' is renamed to
'register_precpu_irq()' & it is directly invoked. Also,
'register_precpu_irq()' is declared in a new header file 'irq.h' inside
'arch/ia64/kernel/', this header file is included by C files invoking
'register_percpu_irq()'.

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/time.c

@@ -32,6 +32,7 @@
 #include <asm/sections.h>
 
 #include "fsyscall_gtod_data.h"
+#include "irq.h"
 
 static u64 itc_get_cycles(struct clocksource *cs);
 
@@ -380,13 +381,6 @@ static u64 itc_get_cycles(struct clocksource *cs)
 	return now;
 }
 
-
-static struct irqaction timer_irqaction = {
-	.handler =	timer_interrupt,
-	.flags =	IRQF_IRQPOLL,
-	.name =		"timer"
-};
-
 void read_persistent_clock64(struct timespec64 *ts)
 {
 	efi_gettimeofday(ts);
@@ -395,7 +389,8 @@ void read_persistent_clock64(struct timespec64 *ts)
 void __init
 time_init (void)
 {
-	register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
+	register_percpu_irq(IA64_TIMER_VECTOR, timer_interrupt, IRQF_IRQPOLL,
+			    "timer");
 	ia64_init_itm();
 }