Kconfig: Remove HAS_IOMEM dependency for Graphics support

The 'commit e25df120

 ("[S390] Kconfig: menus with depends on HAS_IOMEM.")'
added the HAS_IOMEM dependecy for "Graphics support". This disabled the
"Graphics support" menu for S390. But if we enable VT layer for S390,
we would also need to enable the dummy console. So let's remove the
HAS_IOMEM dependency.

Move this dependency to sub menu items and console drivers that use
io memory.

Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <6e8ef238162df5be4462126be155975c722e9863.1519315352.git.alifm@linux.vnet.ibm.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>