media: atmel: atmel-isc: specialize driver name constant

The driver name constant must defined based on product driver, thus moving
the constant directly where it's required. This will allow each ISC based
product to define it's own name.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>