libmediactl: get rid of memset via using calloc
libmediactl: get rid of memset via using calloc

The code snippet
	x = malloc(sizeof(*x));
	memset(x, 0, sizeof(*x));
could be easily changed to
	x = calloc(1, sizeof(*x));

Signed-off-by: Andy Shevchenko <74f0c009df510614346aa771cd21959b78cdb413@linux.intel.com>

baileyji/media-ctl,suapapa/media-ctl,RobertCNelson/media-ctl,suapapa/media-ctl