arm/mpu: Implement stubs for ioremap_attr on MPU

Implement ioremap_attr() stub for MPU system; the
implementation of ioremap() is the same between MMU
and MPU system, and it relies on ioremap_attr(), so
move the definition from mmu/pt.c to arm/mm.c.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

xen/arch/arm/mm.c

@@ -395,6 +395,11 @@ unsigned long get_upper_mfn_bound(void)
     return max_page - 1;
 }
 
+void *ioremap(paddr_t pa, size_t len)
+{
+    return ioremap_attr(pa, len, PAGE_HYPERVISOR_NOCACHE);
+}
+
 /*
  * Local variables:
  * mode: C

xen/arch/arm/mmu/pt.c

@@ -223,11 +223,6 @@ void *ioremap_attr(paddr_t start, size_t len, unsigned int attributes)
     return ptr + offs;
 }
 
-void *ioremap(paddr_t pa, size_t len)
-{
-    return ioremap_attr(pa, len, PAGE_HYPERVISOR_NOCACHE);
-}
-
 static int create_xen_table(lpae_t *entry)
 {
     mfn_t mfn;

xen/arch/arm/mpu/mm.c

@@ -17,6 +17,12 @@ static void __init __maybe_unused build_assertions(void)
     BUILD_BUG_ON(PAGE_SIZE != SZ_4K);
 }
 
+void __iomem *ioremap_attr(paddr_t start, size_t len, unsigned int flags)
+{
+    BUG_ON("unimplemented");
+    return NULL;
+}
+
 /*
  * Local variables:
  * mode: C