kirkwood: solidify SATA_PMP config

kirkwood: solidify SATA_PMP config

SATA_PMP option is no longer exposed when no SATA host driver is enabled
since upstream linux commit bd322af15ce9 ("ata: make SATA_PMP option
selectable only if any SATA host driver is enabled").

Commit 1bb3f593ee73 ("kirkwood: update config for kernel 5.10") manually
added CONFIG_SATA_PMP=y to config file, but the config will disappear for
every kernel_oldconfig refresh.

To prevent this, a small hack is added, which selects SATA_HOST
automatically when SATA_PMP is enabled. This patch can be dropped if
SATA_MV is ever re-added into kernel config file.

Tested-by: Pawel Dembicki <paweldembicki@gmail.com>
Signed-off-by: Sungbo Eo <mans0n@gorani.run>
[Move patch to generic/hack-5.10]
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>