drm/i915: Capture module parameters for the GPU error state

They include useful material such as what mode the VM address space is
running in, what submission mode, extra quirks, etc.

v2: Undef the right macro, use type specific pretty printers
v3: Use strcmp(TYPENAME) rather than creating per-type pretty printers
v4: Use __always_inline to force GCC to eliminate the calls to strcmp and
generate the right call to seq_printf for each parameter.
v5: With the strcmp elimination, we can now use BUILD_BUG to ensure
there are no unhandled types, also use __builtin_strcmp to make it look
even more magic.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170206213608.31328-3-chris@chris-wilson.co.uk