net/fec: consolidate all i.MX options to CONFIG_ARM

Moreover stop listing all i.MX platforms featuring a FEC, and use
the platform's config symbol that selects registration of a fec device
instead.  This might make it easier to add new platforms.

Set default = y for ARMs having a fec to reduce defconfig sizes.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/net/Kconfig

@@ -1944,7 +1944,8 @@ config 68360_ENET
 config FEC
 	bool "FEC ethernet controller (of ColdFire and some i.MX CPUs)"
 	depends on M523x || M527x || M5272 || M528x || M520x || M532x || \
-		MACH_MX27 || ARCH_MX35 || ARCH_MX25 || ARCH_MX5 || SOC_IMX28
+		IMX_HAVE_PLATFORM_FEC || MXS_HAVE_PLATFORM_FEC
+	default IMX_HAVE_PLATFORM_FEC || MXS_HAVE_PLATFORM_FEC if ARM
 	select PHYLIB
 	help
 	  Say Y here if you want to use the built-in 10/100 Fast ethernet

drivers/net/fec.c

@@ -54,7 +54,7 @@
 
 #include "fec.h"
 
-#if defined(CONFIG_ARCH_MXC) || defined(CONFIG_SOC_IMX28)
+#if defined(CONFIG_ARM)
 #define FEC_ALIGNMENT	0xf
 #else
 #define FEC_ALIGNMENT	0x3
@@ -147,8 +147,7 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address");
  * account when setting it.
  */
 #if defined(CONFIG_M523x) || defined(CONFIG_M527x) || defined(CONFIG_M528x) || \
-    defined(CONFIG_M520x) || defined(CONFIG_M532x) || \
-    defined(CONFIG_ARCH_MXC) || defined(CONFIG_SOC_IMX28)
+    defined(CONFIG_M520x) || defined(CONFIG_M532x) || defined(CONFIG_ARM)
 #define	OPT_FRAME_SIZE	(PKT_MAXBUF_SIZE << 16)
 #else
 #define	OPT_FRAME_SIZE	0