drm/xe/mmio: fix build warning for BAR resize on 32-bit

clang complains about a nonsensical test on builds with a 32-bit phys_addr_t,
which means resizing will always fail:

drivers/gpu/drm/xe/xe_mmio.c:109:23: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
  109 |                     root_res->start > 0x100000000ull)
      |                     ~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~

Previously, BAR resize was always disallowed on 32-bit kernels, but
this apparently changed recently. Since 32-bit machines can in theory
support PAE/LPAE for large address spaces, this may end up useful,
so change the driver to shut up the warning but still work when
phys_addr_t/resource_size_t is 64 bit wide.

Fixes: 9a6e6c14 ("drm/xe/mmio: Use non-atomic writeq/readq variant for 32b")
Fixes: 237412e4 ("drm/xe: Enable 32bits build")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226124736.1272949-2-arnd@kernel.orgSigned-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

drivers/gpu/drm/xe/xe_mmio.c

@@ -106,7 +106,7 @@ static void xe_resize_vram_bar(struct xe_device *xe)
 
 	pci_bus_for_each_resource(root, root_res, i) {
 		if (root_res && root_res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
-		    root_res->start > 0x100000000ull)
+		    (u64)root_res->start > 0x100000000ul)
 			break;
 	}