ata: pata_at91: depend on !ARCH_MULTIPLATFORM

Until the driver is corrected to stop using mach/at91isam9_smc.h, it won't
compile in a ARCH_MULTIPLATFORM configuration.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/Kconfig

@@ -835,6 +835,7 @@ config PATA_AT32
 config PATA_AT91
 	tristate "PATA support for AT91SAM9260"
 	depends on ARM && SOC_AT91SAM9
+	depends on !ARCH_MULTIPLATFORM
 	help
 	  This option enables support for IDE devices on the Atmel AT91SAM9260 SoC.