ARM: exynos_defconfig: Remove old non-working MIPI driver

The Exynos MIPI driver does not work anymore (it is board file only) so
it is removed.  Remove also config options.

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Donghwa Lee <dh09.lee@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>