ata: pata_cs5536: fix build on 32-bit UML

ata: pata_cs5536: fix build on 32-bit UML

[ Upstream commit fe5b391fc56f77cf3c22a9dd4f0ce20db0e3533f ]

On 32-bit ARCH=um, CONFIG_X86_32 is still defined, so it
doesn't indicate building on real X86 machines. There's
no MSR on UML though, so add a check for CONFIG_X86.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20250606090110.15784-2-johannes@sipsolutions.net
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>