drm/tiny: correctly print `struct resource *` on error

The `res` variable is already a `struct resource *`, don't take the address of it.

Fixes incorrect output:

	simple-framebuffer 9e20dc000.framebuffer: [drm] *ERROR* could not acquire memory range [??? 0xffff4be88a387d00-0xfffffefffde0a240 flags 0x0]: -16

To be correct:

	simple-framebuffer 9e20dc000.framebuffer: [drm] *ERROR* could not acquire memory range [mem 0x9e20dc000-0x9e307bfff flags 0x200]: -16

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Fixes: 9a10c7e6 ("drm/simpledrm: Add support for system memory framebuffers")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.3+
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20231010174652.2439513-1-joey.gouly@arm.com