cert_create: fix makefile to remove executable on 'make realclean'

Spurious whitespace existed in the BINARY shell variable which meant
the cert_tool executable was not being removed on 'make realclean'.

Change-Id: Ibfd2fd17889514f6613e33c6df58d53b9232ec14
Signed-off-by: Jonathan Wright <jonathan.wright@arm.com>
1 file changed