Add support for parsing and traversing IN_FORMATS property blobs. Providing libdrm with this functionality improves consistency and decreases duplication on the client side.
drmModeFormatModifierBlobIterNext() allows the caller to view formats and associated modifiers given a valid property blob. An example is available inside the libdrm unit test, modetest.c.
Signed-off-by: Luigi Santivetti firstname.lastname@example.org