dreport: add hwmon details to the BMC dump

Copy the hwmon details from /sys/class/hwmon/* to hwmon.log
and append the file to the BMC dump

Tested:
/sys/class/hwmon/hwmon0/in1_max_alarm: 0
/sys/class/hwmon/hwmon0/curr2_crit_alarm: 0
/sys/class/hwmon/hwmon0/temp5_crit: -500

Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
Change-Id: I20a2f20323a9d5095eac0cede46595a2e011ba9f