fix: enable FUSION_SPI driver

It seems to be used by VMWare when virtualizing storage device as a SCSI
disk.

Investigation by James Ringer from the community Slack.

```
udevadm info -a -n /dev/sda | grep -oP 'DRIVERS?=="\K[^"]+'
sd
mptspi
```

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

kernel/build/config-amd64

@@ -2295,7 +2295,7 @@ CONFIG_DM_MULTIPATH=m
 # CONFIG_DM_AUDIT is not set
 # CONFIG_TARGET_CORE is not set
 CONFIG_FUSION=y
-# CONFIG_FUSION_SPI is not set
+CONFIG_FUSION_SPI=m
 CONFIG_FUSION_SAS=m
 CONFIG_FUSION_MAX_SGE=128
 # CONFIG_FUSION_CTL is not set