sh: remove support for sh7300 and solution engine 7300

This patch removes old dead code:
- kill off sh7300 cpu support
- get rid of broken solution engine 7300 board support

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/bugs.h b/include/asm-sh/bugs.h
index d5d7a16..b66139f 100644
--- a/include/asm-sh/bugs.h
+++ b/include/asm-sh/bugs.h
@@ -29,7 +29,7 @@
 		*p++ = '2';
 		*p++ = 'a';
 		break;
-	case CPU_SH7705 ... CPU_SH7300:
+	case CPU_SH7705 ... CPU_SH7729:
 		*p++ = '3';
 		break;
 	case CPU_SH7750 ... CPU_SH4_501: