SFF-8472 Rx power conversion function incorrect

https://github.com/sonic-net/sonic-platform-common/blob/2606cd5fb0a58fc956577602235a9f8f84a887c6/sonic_platform_base/sonic_sfp/sff8472.py#L831-L871

SFF-8472 section 9.3

The specification states, under 5)
Received power, RX_PWR, is given in uW by the following equation:

Rx_PWR (uW) = Rx_PWR(4) * Rx_PWR_ADe4 (16 bit unsigned integer) +
           Rx_PWR(3) * Rx_PWR_ADe3 (16 bit unsigned integer) +
           Rx_PWR(2) * Rx_PWR_ADe2 (16 bit unsigned integer) +
           Rx_PWR(1) * Rx_PWR_AD (16 bit unsigned integer) +
           Rx_PWR(0)

which means Rx_PWR_AD is raised to the power of 4, 3 and 2 respectively in the expression. The comment and code does not reflect that.

Furthermore, the calibration constants are stored in IEEE Std 754 single precision float format in the device. These cannot be treated as integers, as is done in the code.

Start with sonic_platform_base/sonic_sfp/sff8472.py around lines 831-871 and compare the implementation with SFF-8472 section 9.3. Verify how the received-power calibration constants are represented in the device, then correct the power expression and constant handling. Done means the function follows the specified polynomial and interprets the constants as IEEE 754 single-precision floats.