Please apply 8f15c682ac5a (rcutorture: Automatically create initrd directory) to 4.19

[Joel Fernandes <joel@joelfernandes.org>]

Hello,

Could you please apply 8f15c682ac5a ("rcutorture: Automatically create initrd
directory") to 4.19 stable kernels. The patch made it in 5.0.

This is required to make rcutorture work, without it I get build failures
like so:

CC      arch/x86/mm/init_64.o
CC      arch/x86/kernel/cpu/mcheck/mce.o
/home/joelaf/repo/chromiumos/chromiumos/src/third_party/kernel/v4.19/arch/x86/entry/entry_64.S:
Assembler messages:
/home/joelaf/repo/chromiumos/chromiumos/src/third_party/kernel/v4.19/arch/x86/entry/entry_64.S:1762:
Warning: no instruction mnemonic suffix given and no register operands;
using default for `sysret'
AS      arch/x86/realmode/rm/stack.o
CC      arch/x86/kernel/cpu/microcode/core.o
AR      arch/x86/crypto/built-in.a
CC      mm/filemap.o
CC      arch/x86/entry/vdso/vma.o
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c2:
unsupported intra-function call
arch/x86/entry/entry_64.o: warning: objtool: If this is a
retpoline, please patch it in with alternatives and annotate it
with ANNOTATE_NOSPEC_ALTERNATIVE.
CC      arch/x86/kernel/cpu/mtrr/mtrr.o
AS      arch/x86/realmode/rm/reboot.o
AS      arch/x86/realmode/rm/wakeup_asm.o
CC      kernel/bpf/core.o
CC      fs/autofs/init.o
CC      arch/x86/realmode/rm/wakemain.o
CC      fs/debugfs/inode.o
CC      arch/x86/realmode/rm/video-mode.o
CC      arch/x86/entry/vsyscall/vsyscall_64.o
/home/joelaf/repo/chromiumos/chromiumos/src/third_party/kernel/v4.19/usr/gen_initramfs_list.sh:
Cannot open
'/home/joelaf/repo/chromiumos/chromiumos/src/third_party/kernel/v4.19/tools/testing/selftests/rcutorture/initrd'
`]

thanks,

 - Joel