tx25: fix crash while booting Linux

Currently booting Linux on TX25 board doesn't work
since there is no correct mach-id and boot parameters
setup for tx25 board. Fix it now.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: John Rigby <jcrigby@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/board/karo/tx25/tx25.c b/board/karo/tx25/tx25.c
index 4d6a96d..2608698 100644
--- a/board/karo/tx25/tx25.c
+++ b/board/karo/tx25/tx25.c
@@ -145,6 +145,9 @@
 
 	mx25_uart_init_pins();
 #endif
+	/* board id for linux */
+	gd->bd->bi_arch_number = MACH_TYPE_TX25;
+	gd->bd->bi_boot_params = PHYS_SDRAM_1 + 0x100;
 	return 0;
 }