[ARM] arm32ve: arm64: Set TEXT_BASE to 0x10000000

Currently, we use 0x00000000 as TEXT_BASE for arm32ve and arm64
ports. This means all Xvisor virtual address (i.e. VAPOOL) for
arm32ve and arm64 will start at 0x00000000. In other words,
0x00000000 will be a valid address when TEXT_BASE is 0x00000000
hence any buggy code accessing NULL pointers will corrupt Xvisor
code.

Ideally, any NULL pointer access by buggy code should be trapped
so that we can dump register state & stack trace for debugging.

This patch sets TEXT_BASE to 0x10000000 (i.e. skipping first
256MB of virtual addresses) so that we get data abort when some
buddy code tries to access virtual address between 0x00000000 to
0x10000000.

Signed-off-by: Anup Patel <anup@brainfault.org>