x86, pat: ioremap to follow same PAT restrictions as other PAT users

ioremap has this hard-coded check for new type and requested type. That
check differs from other PAT users like /dev/mem mmap, remap_pfn_range
in only one condition where requested type is UC_MINUS and new type
is WC. Under that condition, ioremap fails. But other PAT interfaces succeed
with a WC mapping.

Change to make ioremap be in sync with other PAT APIs and use the same
macro as others. Also changes the error print to KERN_ERR instead of
pr_debug.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/mm/ioremap.c

@@ -228,24 +228,13 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 	retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
 						prot_val, &new_prot_val);
 	if (retval) {
-		pr_debug("Warning: reserve_memtype returned %d\n", retval);
+		printk(KERN_ERR "ioremap reserve_memtype failed %d\n", retval);
 		return NULL;
 	}
 
 	if (prot_val != new_prot_val) {
-		/*
-		 * Do not fallback to certain memory types with certain
-		 * requested type:
-		 * - request is uc-, return cannot be write-back
-		 * - request is uc-, return cannot be write-combine
-		 * - request is write-combine, return cannot be write-back
-		 */
-		if ((prot_val == _PAGE_CACHE_UC_MINUS &&
-		     (new_prot_val == _PAGE_CACHE_WB ||
-		      new_prot_val == _PAGE_CACHE_WC)) ||
-		    (prot_val == _PAGE_CACHE_WC &&
-		     new_prot_val == _PAGE_CACHE_WB)) {
-			pr_debug(
+		if (!is_new_memtype_allowed(prot_val, new_prot_val)) {
+			printk(KERN_ERR
 		"ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n",
 				(unsigned long long)phys_addr,
 				(unsigned long long)(phys_addr + size),