parisc: Initialize the fault vector earlier in the boot process.
A fault vector on parisc needs to be 2K aligned. Furthermore the checksum of the fault vector needs to sum up to 0 which is being calculated and written at runtime. Up to now we aligned both PA20 and PA11 fault vectors on the same 4K page in order to easily write the checksum after having mapped the kernel read-only (by mapping this page only as read-write). But when we want to map the kernel text and data on huge pages this makes things harder. So, simplify it by aligning both fault vectors on 2K boundries and write the checksum before we map the page read-only. Signed-off-by: Helge Deller <email@example.com>