doc: releases: 2.5: add misc x86 to boards and socs

Add misc changes still needed in release notes for
x86 Boards and SoCs after checking their history:
- zefi.py: Use cross compiler while building zephyr
- boards: x86: ehl_crb: Add board variant for Slim Bootloader
- tests: enable the code coverage report for qemu_x86_64
- drivers/timer: Remove legacy APIC driver
- x86: add common memory.ld
- x86: reserve the first megabyte

Signed-off-by: Jennifer Williams <jennifer.m.williams@intel.com>
1 file changed