package/gnu-efi: get rid of patch

Pass TARGET_CONFIGURE_OPTS in the environment instead of on the make command
line, so 'CFLAGS +=' does the right thing in the Makefile without patching.

TARGET_CONFIGURE_OPTS includes TARGET_MAKE_ENV, so drop that.

This does require us to pass CROSS_COMPILE to ensure the native tools are
not used though.

Add a GNU_EFI_MAKE_OPTS and use in both the build and install steps, instead
of repeating the various arguments.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>