mx35: Fix boot hang by avoiding vector relocation

Since commit 3ff46cc4 ("arm: relocate the exception vectors") mx35
does not boot anymore.

Add a specific relocate_vectors macro that skips the vector relocation, as the
i.MX35 SoC does not provide RAM at the high vectors address (0xFFFF0000), and
(0x00000000) maps to ROM.

This allows mx35 to boot again.

Cc: Sebastian Priebe <sebastian.priebe@cadcon.de>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: Stefano Babic <sbabic@denx.de>