[intrinsics] Add existing `unaligned_load`.

core/intrinsics/intrinsics.odin

@@ -41,6 +41,7 @@ mem_copy_non_overlapping :: proc(dst, src: rawptr, len: int) ---
 mem_zero                 :: proc(ptr: rawptr, len: int) ---
 mem_zero_volatile        :: proc(ptr: rawptr, len: int) ---
 
+unaligned_load           :: proc(ptr: ^$T) -> T ---
 
 fixed_point_mul     :: proc(lhs, rhs: $T, #const scale: uint) -> T where type_is_integer(T) ---
 fixed_point_div     :: proc(lhs, rhs: $T, #const scale: uint) -> T where type_is_integer(T) ---