assets: abstract away the firmware assets used for booting

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 <>
Reviewed-by: Patrick Georgi <>
Tested-by: build bot (Jenkins)
14 files changed