Pass --hash-style=both to ld for -z mark-plt tests to support linker
configured with --enable-default-hash-style=gnu.
* testsuite/ld-x86-64/mark-plt-1b-x32.d: Pass --hash-style=both
to ld.
* testsuite/ld-x86-64/mark-plt-1b.d: Likewise.
* testsuite/ld-x86-64/mark-plt-1d-x32.d: Likewise.
* testsuite/ld-x86-64/mark-plt-1d.d: Likewise.
#source: mark-plt-1.s
#as: --x32
-#ld: -melf32_x86_64 -shared -z mark-plt
+#ld: -melf32_x86_64 -shared -z mark-plt --hash-style=both
#objdump: -dw
#...
#source: mark-plt-1.s
#as: --64
-#ld: -melf_x86_64 -shared -z mark-plt
+#ld: -melf_x86_64 -shared -z mark-plt --hash-style=both
#objdump: -dw
#...
#source: mark-plt-1.s
#as: --x32
-#ld: -melf32_x86_64 -shared -z mark-plt -z ibtplt
+#ld: -melf32_x86_64 -shared -z mark-plt -z ibtplt --hash-style=both
#objdump: -dw
#...
#source: mark-plt-1.s
#as: --64
-#ld: -melf_x86_64 -shared -z mark-plt -z ibtplt
+#ld: -melf_x86_64 -shared -z mark-plt -z ibtplt --hash-style=both
#objdump: -dw
#...