powerpc/boot: Only build OPAL code when necessary

Only build the OPAL console code in when necessary. This looks like it
should use CONFIG_PPC_POWERNV, but because the opal-call.S code is
64-bit only, we must only build it when we're building the boot
wrapper 64-bit.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/boot/Makefile

@@ -108,10 +108,10 @@ src-wlib-y := string.S crt0.S stdio.c decompress.c main.c \
 		$(libfdt) libfdt-wrapper.c \
 		ns16550.c serial.c simple_alloc.c div64.S util.S \
 		elf_util.c $(zlib-y) devtree.c stdlib.c \
-		oflib.c ofconsole.c cuboot.c cpm-serial.c \
-		opal.c
+		oflib.c ofconsole.c cuboot.c cpm-serial.c
+
 src-wlib-$(CONFIG_PPC_MPC52XX) += mpc52xx-psc.c
-src-wlib-$(CONFIG_PPC64_BOOT_WRAPPER) +=  opal-calls.S
+src-wlib-$(CONFIG_PPC64_BOOT_WRAPPER) += opal-calls.S opal.c
 ifndef CONFIG_PPC64_BOOT_WRAPPER
 src-wlib-y += crtsavres.S
 endif

arch/powerpc/boot/serial.c

@@ -138,8 +138,10 @@ int serial_console_init(void)
 		 dt_is_compatible(devp, "xlnx,xps-uartlite-1.00.a"))
 		rc = uartlite_console_init(devp, &serial_cd);
 #endif
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
 	else if (dt_is_compatible(devp, "ibm,opal-console-raw"))
 		rc = opal_console_init(devp, &serial_cd);
+#endif
 
 	/* Add other serial console driver calls here */