As there can be more than one source of firmware assets this
patch generalizes the notion of locating a particular asset.
struct asset is added along with some helper functions for
working on assets as a first class citizen.
Change-Id: I2ce575d1e5259aed4c34c3dcfd438abe9db1d7b9
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10264
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
