media: atomisp: convert default struct values to use compound-literals with designated initializers

The CSS API uses a lot of nested anonymous structs defined in object
macros to assign default values to its data-structures.  These have been
changed to use compound-literals and designated initializers to make
them more comprehensible and less fragile.

The compound-literals can also be used in assignment, which means we can
get rid of some temporary variables whose only purpose is to be
initialized by one of these anonymous structs and then serve as the
rvalue in an assignment expression.

A lot of the members of the default struct values used by the CSS API
were explicitly initialized to zero values.  Designated initializers
have allowed these members, and in some case whole default struct
values, to be removed.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>