MAINTAINERS: Adjust EFI entry to removing eboot.c

Commit:

  c2d0b470

 ("efi/libstub/x86: Incorporate eboot.c into libstub")

removed arch/x86/boot/compressed/eboot.[ch], but missed to adjust the
MAINTAINERS entry.

Since then, ./scripts/get_maintainer.pl --self-test complains:

  warning: no file matches F: arch/x86/boot/compressed/eboot.[ch]

Rectify EXTENSIBLE FIRMWARE INTERFACE (EFI) entry in MAINTAINERS.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200301155748.4788-1-lukas.bulwahn@gmail.com
Link: https://lore.kernel.org/r/20200308080859.21568-8-ardb@kernel.org