net: ks8851: Fix mixed module/builtin build

When either the SPI or PAR variant is compiled as module AND the other
variant is compiled as built-in, the following build error occurs:

arm-linux-gnueabi-ld: drivers/net/ethernet/micrel/ks8851_common.o: in function `ks8851_probe_common':
ks8851_common.c:(.text+0x1564): undefined reference to `__this_module'

Fix this by including the ks8851_common.c in both ks8851_spi.c and
ks8851_par.c. The DEBUG macro is defined in ks8851_common.c, so it
does not have to be defined again.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Lukas Wunner <lukas@wunner.de>

drivers/net/ethernet/micrel/Makefile

@@ -5,7 +5,7 @@
 
 obj-$(CONFIG_KS8842) += ks8842.o
 obj-$(CONFIG_KS8851) += ks8851.o
-ks8851-objs = ks8851_common.o ks8851_spi.o
+ks8851-objs = ks8851_spi.o
 obj-$(CONFIG_KS8851_MLL) += ks8851_mll.o
-ks8851_mll-objs = ks8851_common.o ks8851_par.o
+ks8851_mll-objs = ks8851_par.o
 obj-$(CONFIG_KSZ884X_PCI) += ksz884x.o

drivers/net/ethernet/micrel/ks8851_par.c

@@ -8,7 +8,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#define DEBUG
+#include "ks8851_common.c"
 
 #include <linux/interrupt.h>
 #include <linux/module.h>

drivers/net/ethernet/micrel/ks8851_spi.c

@@ -8,7 +8,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#define DEBUG
+#include "ks8851_common.c"
 
 #include <linux/interrupt.h>
 #include <linux/module.h>