ARM: Drop obsolete cell field

Was obsoleted by 8dce90fae3.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
driver/core: Remove size field from hypervisor header

The size field in the hypervisor header is redundant to the information
stored in the system configuration. Change its users and remove the
field.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
driver/core: Move page offset field from header into hypervisor core

No need to pass this information in from the loader driver, needlessly
extending the bootstrap interface. We can perfectly calculate the page
offset during paging setup and store it in a global variable.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
x86: Adjust error code for unsupported APIC configuration

We return -EIO if we hit a hardware configuration that we do not
support.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Documentation: Add bootstrap interface description

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>