m68k: coldfire/device.c: protect FLEXCAN blocks

When CAN_FLEXCAN=y and M5441x is not set/enabled, there are build
errors in coldfire/device.c:

../arch/m68k/coldfire/device.c:595:26: error: 'MCFFLEXCAN_BASE0' undeclared here (not in a function); did you mean 'MCFDMA_BASE0'?
  595 |                 .start = MCFFLEXCAN_BASE0,
../arch/m68k/coldfire/device.c:596:43: error: 'MCFFLEXCAN_SIZE' undeclared here (not in a function)
  596 |                 .end = MCFFLEXCAN_BASE0 + MCFFLEXCAN_SIZE,
../arch/m68k/coldfire/device.c:600:26: error: 'MCF_IRQ_IFL0' undeclared here (not in a function); did you mean 'MCF_IRQ_I2C0'?
  600 |                 .start = MCF_IRQ_IFL0,
../arch/m68k/coldfire/device.c:605:26: error: 'MCF_IRQ_BOFF0' undeclared here (not in a function); did you mean 'MCF_IRQ_I2C0'?
  605 |                 .start = MCF_IRQ_BOFF0,
../arch/m68k/coldfire/device.c:610:26: error: 'MCF_IRQ_ERR0' undeclared here (not in a function); did you mean 'MCF_IRQ_I2C0'?
  610 |                 .start = MCF_IRQ_ERR0,

Protect the FLEXCAN code blocks by checking if MCFFLEXCAN_SIZE
is defined.

Fixes: 35a9f93 ("m68k: m5441x: add flexcan support")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: uclinux-dev@uclinux.org
Cc: Angelo Dureghello <angelo@kernel-space.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

arch/m68k/coldfire/device.c

@@ -581,7 +581,7 @@ static struct platform_device mcf_esdhc = {
 };
 #endif /* MCFSDHC_BASE */
 
-#if IS_ENABLED(CONFIG_CAN_FLEXCAN)
+#ifdef MCFFLEXCAN_SIZE
 
 #include <linux/can/platform/flexcan.h>
 
@@ -620,7 +620,7 @@ static struct platform_device mcf_flexcan0 = {
 	.resource = mcf5441x_flexcan0_resource,
 	.dev.platform_data = &mcf5441x_flexcan_info,
 };
-#endif /* IS_ENABLED(CONFIG_CAN_FLEXCAN) */
+#endif /* MCFFLEXCAN_SIZE */
 
 static struct platform_device *mcf_devices[] __initdata = {
 	&mcf_uart,
@@ -657,7 +657,7 @@ static struct platform_device *mcf_devices[] __initdata = {
 #ifdef MCFSDHC_BASE
 	&mcf_esdhc,
 #endif
-#if IS_ENABLED(CONFIG_CAN_FLEXCAN)
+#ifdef MCFFLEXCAN_SIZE
 	&mcf_flexcan0,
 #endif
 };