Revert "arm64: Use aarch64elf and aarch64elfb emulation mode variants"

This reverts commit 38fc4248.

Distributions such as Fedora and Debian do not package the ELF linker
scripts with their toolchains, resulting in kernel build failures such
as:

  |   CHK     include/generated/compile.h
  |   LD [M]  arch/arm64/crypto/sha512-ce.o
  | aarch64-linux-gnu-ld: cannot open linker script file ldscripts/aarch64elf.xr: No such file or directory
  | make[1]: *** [scripts/Makefile.build:530: arch/arm64/crypto/sha512-ce.o] Error 1
  | make: *** [Makefile:1029: arch/arm64/crypto] Error 2

Revert back to the linux targets for now, adding a comment to the Makefile
so we don't accidentally break this in the future.

Cc: Paul Kocialkowski <contact@paulk.fr>
Cc: <stable@vger.kernel.org>
Fixes: 38fc4248 ("arm64: Use aarch64elf and aarch64elfb emulation mode variants")
Tested-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NLaura Abbott <labbott@redhat.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/Makefile

@@ -60,13 +60,15 @@ ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
 KBUILD_CPPFLAGS	+= -mbig-endian
 CHECKFLAGS	+= -D__AARCH64EB__
 AS		+= -EB
-LDFLAGS		+= -EB -maarch64elfb
+# We must use the linux target here, since distributions don't tend to package
+# the ELF linker scripts with binutils, and this results in a build failure.
+LDFLAGS		+= -EB -maarch64linuxb
 UTS_MACHINE	:= aarch64_be
 else
 KBUILD_CPPFLAGS	+= -mlittle-endian
 CHECKFLAGS	+= -D__AARCH64EL__
 AS		+= -EL
-LDFLAGS		+= -EL -maarch64elf
+LDFLAGS		+= -EL -maarch64linux # See comment above
 UTS_MACHINE	:= aarch64
 endif