core: make the jailhouse-header arch-independent

core: make the jailhouse-header arch-independent

The header of jailhouse is defined with arch-dependent types such as
`unsigned long` which on linux varies in size. Because this header can
be considered the "communication"-relay with the environment, it should
be type-safe on any arch. Thus change all types into fixed-size-types.

Signed-off-by: Benjamin Block <bebl@mageta.org>
[Jan: adjusted jailhouse_entry to keep unsigned int]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>