parisc: parisc-agp requires SBA IOMMU driver

Add a dependency to the SBA IOMMU driver to avoid:
ERROR: modpost: "sba_list" [drivers/char/agp/parisc-agp.ko] undefined!
Reported-by: kernel test robot <lkp@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/char/agp/Kconfig

@@ -125,7 +125,7 @@ config AGP_HP_ZX1
 
 config AGP_PARISC
 	tristate "HP Quicksilver AGP support"
-	depends on AGP && PARISC && 64BIT
+	depends on AGP && PARISC && 64BIT && IOMMU_SBA
 	help
 	  This option gives you AGP GART support for the HP Quicksilver
 	  AGP bus adapter on HP PA-RISC machines (Ok, just on the C8000