sh: Remove config.mk for ap325rxa board

Move CONFIG_SYS_TEXT_BASE to the board's config file, and remove the
unnecessary config.mk file.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/include/configs/ap325rxa.h b/include/configs/ap325rxa.h
index e7f37f5..711dd3c 100644
--- a/include/configs/ap325rxa.h
+++ b/include/configs/ap325rxa.h
@@ -63,6 +63,8 @@
 #define AP325RXA_FLASH_BASE_1		(0xA0000000)
 #define AP325RXA_FLASH_BANK_SIZE	(128 * 1024 * 1024)
 
+#define CONFIG_SYS_TEXT_BASE	0x8FFC0000
+
 /* undef to save memory	*/
 #define CONFIG_SYS_LONGHELP
 /* Monitor Command Prompt */