x86/xen: Fix kerneldoc warning

Fix the following W=1 kernel warnings:

arch/x86/xen/setup.c:725: warning: expecting prototype for
machine_specific_memory_setup(). Prototype was for xen_memory_setup()
instead.

Reported-by: Abaci Robot <[email protected]>
Signed-off-by: Jiapeng Chong <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Boris Ostrovsky <[email protected]>

Author: Jiapeng Chong

arch/x86/xen/setup.c

@@ -719,7 +719,7 @@ static void __init xen_reserve_xen_mfnlist(void)
 }
 
 /**
- * machine_specific_memory_setup - Hook for machine specific memory setup.
+ * xen_memory_setup - Hook for machine specific memory setup.
  **/
 char * __init xen_memory_setup(void)
 {