efi/x86: Move command-line initrd loading to efi_main

Consolidate the initrd loading in efi_main.

The command line options now need to be parsed only once.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200430182843.2510180-9-nivedita@alum.mit.edu


Signed-off-by: Ard Biesheuvel <ardb@kernel.org>