[media] media: exynos4-is: add flags to dummy Exynos IS i2c adapter

Add simple 'functionality' member to dummy Exynos IS i2c adapter to make
i2c core happy and get rid of NULL pointer dereference during Exynos4 IS
probe since v4.10-rc1:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 100 Comm: kworker/1:2 Not tainted 4.10.0-rc6-next-20170131-00054-g39e6e4233de6 #1921
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
Workqueue: events deferred_probe_work_func
task: ef2e0000 task.stack: ef2ec000
PC is at 0x0
LR is at i2c_register_adapter+0x98/0x5cc
...
[<c05040bc>] (i2c_register_adapter) from [<c05379d4>] (fimc_is_i2c_probe+0x84/0xe4)
[<c05379d4>] (fimc_is_i2c_probe) from [<c041b5c8>] (platform_drv_probe+0x50/0xb0)
[<c041b5c8>] (platform_drv_probe) from [<c0419f48>] (driver_probe_device+0x234/0x2dc)
[<c0419f48>] (driver_probe_device) from [<c04184e0>] (bus_for_each_drv+0x44/0x8c)
[<c04184e0>] (bus_for_each_drv) from [<c0419c8c>] (__device_attach+0x9c/0x100)
[<c0419c8c>] (__device_attach) from [<c0419374>] (bus_probe_device+0x84/0x8c)
[<c0419374>] (bus_probe_device) from [<c04178d4>] (device_add+0x380/0x528)
[<c04178d4>] (device_add) from [<c05aceb4>] (of_platform_device_create_pdata+0x70/0xa4)
[<c05aceb4>] (of_platform_device_create_pdata) from [<c05acfd4>] (of_platform_bus_create+0xec/0x320)
[<c05acfd4>] (of_platform_bus_create) from [<c05ad264>] (of_platform_populate+0x5c/0xac)
[<c05ad264>] (of_platform_populate) from [<c0533420>] (fimc_is_probe+0x1c0/0x4cc)
[<c0533420>] (fimc_is_probe) from [<c041b5c8>] (platform_drv_probe+0x50/0xb0)
[<c041b5c8>] (platform_drv_probe) from [<c0419f48>] (driver_probe_device+0x234/0x2dc)
[<c0419f48>] (driver_probe_device) from [<c04184e0>] (bus_for_each_drv+0x44/0x8c)
[<c04184e0>] (bus_for_each_drv) from [<c0419c8c>] (__device_attach+0x9c/0x100)
[<c0419c8c>] (__device_attach) from [<c0419374>] (bus_probe_device+0x84/0x8c)
[<c0419374>] (bus_probe_device) from [<c04197a8>] (deferred_probe_work_func+0x60/0x8c)
[<c04197a8>] (deferred_probe_work_func) from [<c01329a4>] (process_one_work+0x120/0x31c)
[<c01329a4>] (process_one_work) from [<c0132bc8>] (process_scheduled_works+0x28/0x38)
[<c0132bc8>] (process_scheduled_works) from [<c0132ddc>] (worker_thread+0x204/0x4ac)
[<c0132ddc>] (worker_thread) from [<c01381b8>] (kthread+0xfc/0x134)
[<c01381b8>] (kthread) from [<c01078b8>] (ret_from_fork+0x14/0x3c)

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>