tools/imls: fix comment in Makefile

Commit d984fed0 (makefiles: fixes for building build tools)
changed the variable name FIT_CFLAGS to HOSTCFLAGS_NOPED
but forgot to update to corresponding comment.

Signed-off-by: Daniel Hobi <daniel.hobi@schmid-telecom.ch>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Wolfgang Denk <wd@denx.de>