efi: Generalize relocate_kernel() for use by other architectures.

efi: Generalize relocate_kernel() for use by other architectures.

Rename relocate_kernel() to efi_relocate_kernel(), and take
parameters rather than x86 specific structure.  Add max_addr
argument as for ARM we have some address constraints that we
need to enforce when relocating the kernel.  Add alloc_size
parameter for use by ARM64 which uses an uncompressed kernel,
and needs to allocate space for BSS.

Signed-off-by: Roy Franz <roy.franz@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
(cherry picked from commit 4a9f3a7c336a6b0ffeef2523bef93e67b0921163)
Signed-off-by: Mark Brown <broonie@linaro.org>