ARM: 6667/1: Fix early_pte_alloc() assumption about the Linux PTE

With LPAE we no longer have software bits in a separate Linux PTE and
the early_pte_alloc() function should pass PTE_HWTABLE_OFF +
PTE_HWTABLE_SIZE to early_alloc() to avoid allocating extra memory.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>