(prevents inclusion and also issues warning)
Changes to some source files to remove references to common headers.
Changes to rng.h to make guard symbols the same in f2 and f4.
file having its own group module rather than using @file.
No code changes except for the following:
gpio: Added function to map the eventout signal plus two Remap functions
dma: Prevent changing base addresses while channel enabled (see datasheet)
pwr: Added pwr.c (new file)
timer: Removed the last function that I introduced recently; there is already
an equivalent function present. Changed some parameter names for consistency.
