MIPS: Add board_ebase_setup()

Some systems need to relocate the MIPS exception vector base during
trap initialization.  Add a hook to make this possible.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2959/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 33945aa..c18dfd4 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -91,6 +91,7 @@
 void (*board_nmi_handler_setup)(void);
 void (*board_ejtag_handler_setup)(void);
 void (*board_bind_eic_interrupt)(int irq, int regset);
+void (*board_ebase_setup)(void);
 
 
 static void show_raw_backtrace(unsigned long reg29)
@@ -1691,6 +1692,8 @@
 			ebase += (read_c0_ebase() & 0x3ffff000);
 	}
 
+	if (board_ebase_setup)
+		board_ebase_setup();
 	per_cpu_trap_init();
 
 	/*