arm: Allow mounting root on omaps with CPU_V6 and CPU_V7

To mount root, we need to disable VFPv3, HAS_TLS_REG, and
set ARM_L1_CACHE_SHIFT=5.

Otherwise we'll get something like this for CPUv3:

Freeing init memory: 184K
Internal error: Oops - undefined instruction: 0 [#1]
last sysfs file:
Modules linked in:
CPU: 0    Not tainted  (2.6.33-rc8-07824-gf2e1d91-dirty #36)
PC is at no_old_VFP_process+0x8/0x3c
LR is at __und_usr_unknown+0x0/0x14
...

Or the system just hangs if HAS_TLS_REG is set.

The ARM_L1_CACHE_SHIFT most likely will cause issues
too if not set to 5.

Signed-off-by: Tony Lindgren <tony@atomide.com>