[fprint] Export fingerprint readers in libfprint

[Daniel Drake]

Bastien Nocera wrote:
> Patch attached to generate an FDI file from libfprint, and an example
> output. We probably want to move the whole function into libfprint, so
> we can avoid removing the visibility CFLAG.

Agreed, I'd like to keep that.

> What do people think of the namespace used for the capabilities and
> categories? Do those need adding to the HAL spec?

Looks fine at a glance but I don't really know anything about HAL 
namespaces.

One small error: (sorry for bad wrapping)

	printf ("      <merge key=\"info.capabilities\" 
type=\"strlist\">fingerprint-reader</append>\n");

closing tag should be </merge>

Daniel