x86/mm/64: Always use dynamic memory layout

Dynamic memory layout is used by KASLR and 5-level paging.

CONFIG_X86_5LEVEL is going to be removed, making 5-level paging support
unconditional which requires unconditional support of dynamic memory
layout.

Remove CONFIG_DYNAMIC_MEMORY_LAYOUT.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250516123306.3812286-2-kirill.shutemov@linux.intel.com