OvmfPkg/QemuVideoDxe/VbeShim.sh: remove end-of-options delimiter for nasm
    
    Per my bisection: nasm broke the parsing of the "--" end-of-options
    delimiter in commit 55568c1193df ("nasm: scan the command line twice",
    2016-10-03), part of the nasm-2.13 release. The parsing remains broken in
    at least nasm-2.15.03. The (invalid) error message is: "more than one
    input file specified". I've filed the following ticket for upstream nasm
    (and ndisasm): <https://bugzilla.nasm.us/show_bug.cgi?id=3392829>.
    
    Since the delimiter is not necessary in practice (due to $STEM being
    "VbeShim", i.e., not starting with a hyphen), simply remove the delimiter.
    
    Tested by enabling DEBUG in "VbeShim.asm", running the script, building
    OVMF, booting Windows 7, and checking the firmware log (debug console).
    
    Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
    Cc: Gerd Hoffmann <kraxel@redhat.com>
    Cc: Jiewen Yao <jiewen.yao@intel.com>
    Cc: Jordan Justen <jordan.l.justen@intel.com>
    Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3876
    Signed-off-by: Laszlo Ersek <lersek@redhat.com>