configs/qemu_riscv64_virt: update defconfigs to Linux 5.4.35

Contrary to riscv32, the qemu_riscv64_virt defconfig doesn't needs
any specific change. It could have been updated to Linux 5.4.35 in
the commit 80a04470.

So, update the kernel version to 5.4.35.

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>