[Natty SRU, Oneiric] Re-enable RODATA for i386 virtual

[Stefan Bader]

SRU Justification:

Impact: Kernel data is marked as read-only by this option and it is set
for security reasons on all kernel flavours. However it had been disabled
in the i386 virtual flavour because of a bug that would prevent booting
in EC2 (bug #699828).

Fix: This issue is now fixed and it is possible to turn this option back on.

Testcase: Compiled current kernel with the option turned back on and boot
tested on EC2 and local Xen test system.

The following patches are mostly identical, just avoiding some fuzz in
when changing the configs.

-Stefan