media: atomisp: Remove atomisp_sw_contex struct

Remove the atomisp_sw_contex struct, it has only 1 member: running_freq,
instead store running_freq directly.

While at it also change running_freq from an int to an unsigned int,
all values stored in it are unsigned and it is compared to the also
unsigned new_freq variable.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>