docs: move ia64 architecture docs under Documentation/arch/

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.  Move
Documentation/ia64 into arch/ and fix all in-tree references.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/arch/index.rst

@@ -12,7 +12,7 @@ implementation.
    arc/index
    ../arm/index
    ../arm64/index
-   ../ia64/index
+   ia64/index
    ../loongarch/index
    ../m68k/index
    ../mips/index

MAINTAINERS

@@ -9724,7 +9724,7 @@ F:	include/linux/i3c/
 IA64 (Itanium) PLATFORM
 L:	linux-ia64@vger.kernel.org
 S:	Orphan
-F:	Documentation/ia64/
+F:	Documentation/arch/ia64/
 F:	arch/ia64/
 
 IBM Operation Panel Input Driver

arch/ia64/kernel/efi.c

@@ -853,7 +853,7 @@ valid_phys_addr_range (phys_addr_t phys_addr, unsigned long size)
 	 * /dev/mem reads and writes use copy_to_user(), which implicitly
 	 * uses a granule-sized kernel identity mapping.  It's really
 	 * only safe to do this for regions in kern_memmap.  For more
-	 * details, see Documentation/ia64/aliasing.rst.
+	 * details, see Documentation/arch/ia64/aliasing.rst.
 	 */
 	attr = kern_mem_attribute(phys_addr, size);
 	if (attr & EFI_MEMORY_WB || attr & EFI_MEMORY_UC)

arch/ia64/kernel/fsys.S

@@ -28,7 +28,7 @@
 #include <asm/native/inst.h>
 
 /*
- * See Documentation/ia64/fsys.rst for details on fsyscalls.
+ * See Documentation/arch/ia64/fsys.rst for details on fsyscalls.
  *
  * On entry to an fsyscall handler:
  *   r10	= 0 (i.e., defaults to "successful syscall return")

arch/ia64/mm/ioremap.c

@@ -43,7 +43,7 @@ ioremap (unsigned long phys_addr, unsigned long size)
 	/*
 	 * For things in kern_memmap, we must use the same attribute
 	 * as the rest of the kernel.  For more details, see
-	 * Documentation/ia64/aliasing.rst.
+	 * Documentation/arch/ia64/aliasing.rst.
 	 */
 	attr = kern_mem_attribute(phys_addr, size);
 	if (attr & EFI_MEMORY_WB)

arch/ia64/pci/pci.c

@@ -448,7 +448,7 @@ pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma,
 		return -ENOSYS;
 
 	/*
-	 * Avoid attribute aliasing.  See Documentation/ia64/aliasing.rst
+	 * Avoid attribute aliasing.  See Documentation/arch/ia64/aliasing.rst
 	 * for more details.
 	 */
 	if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))