m68k: Fix wrong assembler instruction in start.S

The jmp _fault generated the following error message, thus change it
to bra _fault:

start.S: Assembler messages:
start.S:310: Error: Conversion of PC relative displacement to absolute

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: "Jin Zhengxiong-R64188" <R64188@freescale.com>
Cc: Jason Jin <jason.jin@freescale.com>
4 files changed