rmodule: add ability to calculate module placement

There is a need to calculate the proper placement for an rmodule
in memory. e.g. loading a compressed rmodule from flash into ram
can be an issue. Determining the placement is hard since the header
is not readable until it is decompressed so choosing the wrong location
may require a memmove() after decompression. This patch provides
a function to perform this calculation by finding region below a given
address while making an assumption on the size of the rmodule header..

Change-Id: I2703438f58ae847ed6e80b58063ff820fbcfcbc0
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2788
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2 files changed