build: cleanup Makefile
build: cleanup Makefile

Cleanup the Makefile w.r.t spaces and tabs.

Change-Id: I62b4aadc1ecc0874ce31941dbc0ab557ec8c8b50
Signed-off-by: Patrick Venture <36c53fa43f47f3fd67cb2fc38031827244d18a1f@google.com>

openbmc/phosphor-pid-control,openbmc/phosphor-pid-control