OMAP2+: Kconfig: disallow builds for boards that don't use the currently-selected SoC

Currently, if, for example, CONFIG_ARCH_OMAP2420 is not selected, OMAP2420
board files can still be included in the build.  This results in link errors:

arch/arm/mach-omap2/built-in.o: In function `omap_generic_map_io':
.../arch/arm/mach-omap2/board-generic.c:51: undefined reference to `omap2_set_globals_242x'
arch/arm/mach-omap2/built-in.o: In function `omap_h4_init':
.../arch/arm/mach-omap2/board-h4.c:330: undefined reference to `omap2420_mux_init'
arch/arm/mach-omap2/built-in.o: In function `omap_h4_map_io':
.../arch/arm/mach-omap2/board-h4.c:373: undefined reference to `omap2_set_globals_242x'
arch/arm/mach-omap2/built-in.o: In function `omap_apollon_init':
.../arch/arm/mach-omap2/board-apollon.c:325: undefined reference to `omap2420_mux_init'
arch/arm/mach-omap2/built-in.o: In function `omap_apollon_map_io':
.../arch/arm/mach-omap2/board-apollon.c:353: undefined reference to `omap2_set_globals_242x'
make: *** [.tmp_vmlinux1] Error 1

Fix this by making the boards depend on the Kconfig option for the
specific SoC that they use.

Also, while here, fix the mach-omap2/board-generic.c file to remove the
dependency on OMAP2420.

Charulatha Varadarajan <charu@ti.com> caught a typo - thanks Charu.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Charulatha Varadarajan <charu@ti.com>
diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
index 3482b99..8aee862 100644
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -48,10 +48,22 @@
 
 static void __init omap_generic_map_io(void)
 {
-	omap2_set_globals_242x(); /* should be 242x, 243x, or 343x */
-	omap242x_map_common_io();
+	if (cpu_is_omap242x()) {
+		omap2_set_globals_242x();
+		omap242x_map_common_io();
+	} else if (cpu_is_omap243x()) {
+		omap2_set_globals_243x();
+		omap243x_map_common_io();
+	} else if (cpu_is_omap34xx()) {
+		omap2_set_globals_3xxx();
+		omap34xx_map_common_io();
+	} else if (cpu_is_omap44xx()) {
+		omap2_set_globals_443x();
+		omap44xx_map_common_io();
+	}
 }
 
+/* XXX This machine entry name should be updated */
 MACHINE_START(OMAP_GENERIC, "Generic OMAP24xx")
 	/* Maintainer: Paul Mundt <paul.mundt@nokia.com> */
 	.phys_io	= 0x48000000,