Add an abstraction layer to handle the clock control for the run time clock on
LM4F (RCC). Sleep and deep-sleep clock configuration is not handled.
Complete documentation for the clock control API is included in doxygen-style
comments, and is included in [doc].
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Conflicts:
lib/lm4f/Makefile
7957cffaa3