build: -no-pie is no functional linker flag

Recent binutils changes dropping unsupported options [1] caused a build
issue in regard to the optionroms.

  ld -m elf_i386 -T /<<PKGBUILDDIR>>/pc-bios/optionrom//flat.lds -no-pie \
    -s -o multiboot.img multiboot.o
  ld.bfd: Error: unable to disambiguate: -no-pie (did you mean --no-pie ?)

This isn't really a regression in ld.bfd, filing the bug upstream
revealed that this never worked as a ld flag [2] - in fact it seems we
were by accident setting --nmagic).

Since it never had the wanted effect this usage of LDFLAGS_NOPIE, should be
droppable without any effect. This also is the only use-case of LDFLAGS_NOPIE
in .mak, therefore we can also remove it from being added there.

[1]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=983d925d
[2]: https://sourceware.org/bugzilla/show_bug.cgi?id=27050#c5

Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Message-Id: <20201214150938.1297512-1-christian.ehrhardt@canonical.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

pc-bios/optionrom/Makefile

@@ -41,7 +41,6 @@ override CFLAGS += $(call cc-option, $(Wa)-32)
 
 LD_I386_EMULATION ?= elf_i386
 override LDFLAGS = -m $(LD_I386_EMULATION) -T $(SRC_DIR)/flat.lds
-override LDFLAGS += $(LDFLAGS_NOPIE)
 
 all: multiboot.bin linuxboot.bin linuxboot_dma.bin kvmvapic.bin pvh.bin