efi/x86: Fix the missing KASLR_FLAG bit in boot_params->hdr.loadflags

When KASLR is enabled, the KASLR_FLAG bit in boot_params->hdr.loadflags
should be set to 1 to propagate KASLR status from compressed kernel to
kernel, just as the choose_random_location() function does.

Currently, when the kernel is booted via the EFI stub, the KASLR_FLAG
bit in boot_params->hdr.loadflags is not set, even though it should be.
This causes some functions, such as kernel_randomize_memory(), not to
execute as expected. Fix it.

Fixes: a1b87d54 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
[ardb: drop 'else' branch clearing KASLR_FLAG]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>