[IA64] Remove warnings for gcc 4.0 IA64 compilation.

This patch removes some compilation warnings, mostly
trivially. acpi.c fix also noted by Kenji Kaneshige.

Signed-off-by; Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index ba0b6a1..0741b066 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -491,7 +491,7 @@
 	;;
 	lfetch.fault [r16], 128
 	br.ret.sptk.many rp
-END(prefetch_switch_stack)
+END(prefetch_stack)
 
 GLOBAL_ENTRY(execve)
 	mov r15=__NR_execve			// put syscall number in place