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: NMike Frysinger <vapier@gentoo.org>

arch/m68k/cpu/mcf52x2/cpu_init.c

@@ -284,7 +284,7 @@ void cpu_init_f(void)
 	mbar_writeLong(MCF_FMPLL_SYNCR,
 			MCF_FMPLL_SYNCR_MFD(0) | MCF_FMPLL_SYNCR_RFD(0));
 #endif
-	while (!mbar_readByte(MCF_FMPLL_SYNSR) & MCF_FMPLL_SYNSR_LOCK) ;
+	while (!(mbar_readByte(MCF_FMPLL_SYNSR) & MCF_FMPLL_SYNSR_LOCK)) ;
 }
 
 /*