[IA64] Fix boot failure on ia64/sn2

Call check_sal_cache_flush() after platform_setup() as
check_sal_cache_flush() now relies on being able to call platform
vector code.

Problem was introduced by: 3463a93d
"Update check_sal_cache_flush to use platform_send_ipi()"
Signed-off-by: NJes Sorensen <jes@sgi.com>
Tested-by: NAlex Chiang: <achiang@hp.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

arch/ia64/kernel/setup.c

@@ -578,8 +578,6 @@ setup_arch (char **cmdline_p)
 	cpu_init();	/* initialize the bootstrap CPU */
 	mmu_context_init();	/* initialize context_id bitmap */
 
-	check_sal_cache_flush();
-
 #ifdef CONFIG_ACPI
 	acpi_boot_init();
 #endif
@@ -607,6 +605,7 @@ setup_arch (char **cmdline_p)
 		ia64_mca_init();
 
 	platform_setup(cmdline_p);
+	check_sal_cache_flush();
 	paging_init();
 }