mvebu: kernel: enable CONFIG_BLK_DEV_NVME

mvebu: kernel: enable CONFIG_BLK_DEV_NVME

CONFIG_BLK_DEV_NVME [1]:
- This is a kernel driver for SSD connected to PCI or PCIe bus [1].
By default, it is enabled for targets "ipq807x", "rockchip/armv8"
and "x86/64".

With miniPCIe adapter, there is a possibility to connect NVMe disk
to Turris Omnia (cortex-a9), Turris MOX (cortex-a53).

It allows to boot system from NVMe disk, because of that it can not
be kmod package as you can not access the disk to be able to boot from
it.

CONFIG_NVME_CORE [2]:
- This is selected by CONFIG_BLK_DEV_NVME
It does not need to be explicitly enabled, but it is done for "ipq807",
"x64_64" and rockchip/armv8", which has also enabled the previous config
option as well.

Kernel increase: ~28k KiB on mamba kernel

Reference:
[1] https://cateee.net/lkddb/web-lkddb/BLK_DEV_NVME.html
[2] https://cateee.net/lkddb/web-lkddb/NVME_CORE.html

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>
(cherry picked from commit 9d530ac4bf6b9804a06dbf5df4631ee86f1304c1)
[rebased for config-5.4]