Add missing registers for more than 4 strings

[olivergregorius]

The register definitions for the inverter equipment, number 18 in the documentation says:

A maximum of 24 PV strings are supported. The number of PV strings read by the host is defined by the Number of PV strings signal. The voltage and current register addresses for each PV string are as follows:
PVn voltage 32014 + 2n
PVn current 32015 + 2n
n indicates the PV string number, which ranges from 1 to 24.

According to this remark the missing registers should be added to the registers in this library.