[alpha] scsi: Disable SCSI_IMM (fixes FTBFS)
- The mos7720 USB serial driver is enabled everywhere, and is included in the usb-serial-modules udeb.
- The imm parallel-port SCSI driver is enabled on alpha only, and is included in the scsi-modules udeb.
- They both depend on parport, which isn't included in any modules list, so it ends up in both of the above udebs and the build fails.
I previously disabled imm (CONFIG_SCSI_IMM) in 2013, but it was re-enabled by mistake in commit 9eaeca93 ("d/config: Update with the help of kconfigeditor2"). Disable it again, along with the dependent CONFIG_SCSI_IZIP_SLOW_CTR symbol.
Fixes: 9eaeca93 ("d/config: Update with the help of kconfigeditor2")