m68k: fix ambiguous bit testing

Building for some m68k boards results in the warning:

cpu_init.c: In function 'cpu_init_f':
cpu_init.c:287: warning: suggest parentheses around
	operand of '!' or change '&' to '&&' or '!' to '~'

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
1 file changed