Use the correct value for the offset of 'kve_protection'.

Use the correct value for the offset of 'kve_protection'.

I had forgotten to convert the decimal output of 'ptype /o' to hex
(but still used a 0x prefix) for the KVE_PROTECTION constant defining
the offset of the 'kve_protection' field in the 'kinfo_vmentry'
structure.  This resulted in garbage permissions for entries in 'info
proc mappings' for FreeBSD core dumps.

gdb/ChangeLog:

	* fbsd-tdep.c (KVE_PROTECTION): Correct value.