ARM: 8681/1: make VMSPLIT_3G_OPT depends on !ARM_LPAE

When both enable CONFIG_ARM_LPAE=y and CONFIG_VMSPLIT_3G_OPT=y, which
means use PAGE_OFFSET=0xB0000000 with ARM_LPAE, the kernel will boot
fail and stop after uncompressed:

   Starting kernel ...

   Uart base = 0x20001000
   watchdog reg = 0x20013000
   dtb addr = 0x80840308
   Uncompressing Linux... done, booting the kernel.

For ARM_LPAE only support 3:1, 2:2, 1:3 split of TTBR1, which mention in:
   http://elinux.org/images/6/6a/Elce11_marinas.pdf

 - p16

So we should make VMSPLIT_3G_OPT depends on !ARM_LPAE to avoid trigger
this bug.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>