optoe: Add CMIS Bank support for transceivers with >8 lanes

[ishidawataru]

This patch adds CMIS Bank support to the 'optoe3' device class in order
to enable access to CMIS transceivers with more than 8 lanes (e.g., OSFP-XD, CPO OEs).

• Bank support is enabled only for the 'optoe3' dev class.
• The default bank size is set to 4, and can be modified via the 'bank_size' sysfs entry.
• For 'optoe3', the 'write_max' value is updated to 2 to comply with CMIS requirements,
  which mandate that both bank and page values be updated in a single WRITE operation.

Updated the behavior as below after discussing with @prgeor offline

• 'bank_size' sysfs entry is added to enable and configure the size of the bank.
• By default, bank size is set to 0.
• When enabling bank by setting a value greater than 1, the 'write_max' value is
  automatically updated to 2 to comply with CMIS requirements,
  which mandate that both bank and page values be updated in a single WRITE operation.
• If the 'write_max' value is already greater than 2, this module keeps the value as is.

Only tested with the SONiC VM + i2c-stub.

admin@sonic:~$ cat /sys/class/i2c-dev/i2c-1/device/1-0050/bank_size
4
admin@sonic:~$ hexdump /sys/class/i2c-dev/i2c-1/device/1-0050/eeprom 
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*
001e880
admin@sonic:~$ echo 1 | sudo tee /sys/class/i2c-dev/i2c-1/device/1-0050/bank_size
1
admin@sonic:~$ hexdump /sys/class/i2c-dev/i2c-1/device/1-0050/eeprom 
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*
0008080

Snip of dmesg. See bank:3 is accessed.

[140341.928384] optoe 1-0050: eeprom write 2@126 --> 2 (4329977748)
[140341.928386] optoe 1-0050: sff_r/w: off 122880, len 2176, chunk_start_offset 124928, chunk_offset 124928, chunk_len 128, pending_len 128
[140341.928388] optoe 1-0050: optoe_eeprom_update_client off 124928 bank:3 page:255 phy_offset:128, count:128, opcode:0
[140341.928391] optoe 1-0050: eeprom write 2@126 --> 2 (4329977748)
[140341.928393] optoe 1-0050: eeprom read 32@128 --> 32 (4329977748)
[140341.928395] optoe 1-0050: eeprom read 32@160 --> 32 (4329977748)
[140341.928397] optoe 1-0050: eeprom read 32@192 --> 32 (4329977748)
[140341.928399] optoe 1-0050: eeprom read 32@224 --> 32 (4329977748)
[140341.928401] optoe 1-0050: eeprom write 2@126 --> 2 (4329977748)
[140341.928413] optoe 1-0050: optoe_read_write: off 125056  len:4096, opcode:r

Not tested with real hardware yet.