Add Areca enclosure number support to SMART

On a system with an Areca HBA, smartd fails to start and coredumps and multiple instances of smartctl (invoked one process per disk) chew up all CPU resourecs as they spin on CPU.

As the smartd binary is stripped, I'm not getting much from pointing gdb at the core file.

Core was generated by `smartctl -i /dev/arcmsr0 -d areca,15'.
Program terminated with signal SIGBUS, Bus error.
#0 0x000000080176c1d4 in memcpy () from /lib/libc.so.7
(gdb) bt
#0 0x000000080176c1d4 in memcpy () from /lib/libc.so.7
#1 0x0000000000439d71 in ?? ()
#2 0x000000000042302e in ?? ()
#3 0x0000000000422eac in ?? ()
#4 0x000000000042c8c2 in ?? ()
#5 0x0000000000404268 in ?? ()
#6 0x0000000000403635 in ?? ()
#7 0x00000008006a9000 in ?? ()
#8 0x0000000000000000 in ?? ()

The card I'm using is an ARC-1882ix-24 with the latest firmware

arcmsr0: <Areca SAS 6G Host Adapter RAID Controller (RAID6 capable)
arcmsr version 1.40.00.01 2017-10-30
arcmsr: MSI-X INT enabled

I believe the issues is that as the card has internal and external ports, smartctl has to be invoked with the channel/enclosure specfied. from smartctl(8)

areca,N/E - [FreeBSD, Linux, Windows and Cygwin only] the device
consists of one or more SATA or SAS disks connected to an Areca
SAS RAID controller. The integer N (range 1 to 128) denotes the
channel (slot) and E (range 1 to 8) denotes the enclosure.
Important: This requires Areca SAS controller firmware version
1.51 or later

e.g

smartctl -i /dev/arcmsr0 -d areca,14

doesn't work, but

smartctl -i /dev/arcmsr0 -d areca,14/2

does work.

For smartd, I have to compose a manual config file with the disk specified like so

/dev/arcmsr0 -d areca,1/2 -a
/dev/arcmsr0 -d areca,2/2 -a

and then it is happy to run.