mdadm: load default sysfs attributes after assemblation

mdadm: load default sysfs attributes after assemblation

Added new type of line to mdadm.conf which allows to specify values of
sysfs attributes for MD devices that should be loaded after the array is
assembled. Each line is interpreted as list of structures containing
sysname of MD device (md126 etc.) and list of sysfs attributes and their
values.

Signed-off-by: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Signed-off-by: Krzysztof Smolinski <krzysztof.smolinski@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>