CFLAGS in the makefile were being specified incorrectly.
- the single quotes for forcing all options to be passed as a single
token by the shell.
- Specifying -static and -lc via -Wl is not needed.
This allows clients to use the instrument more easily from their code
if they were previously used to using an HWMON-style interface.
In order to provide the measurement, the existing readenergy binary
is updated and changed so that if no output option is specified then
we just print the current values and exit.
Signed-off-by: Chris Redpath <chris.redpath@arm.com>