libs/utils/energy: report the start of HWMON scanning
libs/utils/energy: report the start of HWMON scanning

The scanning of HWMON channels performed by the devlib library could take
some time during which we do not see any progress in the console.

This patch adds an INFO statement to notice the user that a scanning is
in progress.

Signed-off-by: Patrick Bellasi <431c86f368affbc3148c4669fbd465131f7e82cb@arm.com>

ARM-software/lisa,credp/lisa,credp/lisa,ARM-software/lisa,mdigiorgio/lisa,arnoldlu/lisa,credp/lisa,joelagnel/lisa,credp/lisa,joelagnel/lisa,arnoldlu/lisa,ARM-software/lisa,bjackman/lisa,JaviMerino/lisa,ARM-software/lisa,bjackman/lisa,mdigiorgio/lisa