i2c: designware: Consolidate firmware parsing and configuring code

i2c: designware: Consolidate firmware parsing and configuring code

We have the same code flows in the PCI and platform drivers. Moreover,
the flow requires the common code to export a few functions. Instead,
consolidate that flow under new function called
i2c_dw_fw_parse_and_configure() and drop unneeded exports.

Reviewed-by: Andi Shyti <[email protected]>
Reviewed-by: Mario Limonciello <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Andi Shyti <[email protected]>