vpfe_capture: Add call back function for interrupt clear for vpfe_cfg

For the devices like AM3517, it is expected that driver clears the
interrupt in ISR. Since this is device spcific, callback function
added to the platform_data.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Muralidharan Karicheri <mkaricheri@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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