thermal: power_allocator: allocate with kcalloc what you free with kfree

Commit cf736ea6 ("thermal: power_allocator: do not use devm*
interfaces") forgot to change a devm_kcalloc() to just kcalloc(), but
it's corresponding devm_kfree() was changed to kfree().  Allocate with
kcalloc() to match the kfree().

Fixes: cf736ea6

 ("thermal: power_allocator: do not use devm* interfaces")
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>