Fix i2c_readReg16

[zvecr]

Description

Currently producing the following build error,

Compiling: platforms/chibios/drivers/i2c_master.c                                                  platforms/chibios/drivers/i2c_master.c: In function 'i2c_readReg16':
platforms/chibios/drivers/i2c_master.c:140:92: error: passing argument 3 of 'i2cMasterTransmitTimeout' from incompatible pointer type [-Werror=incompatible-pointer-types]
  140 |     msg_t   status             = i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), &register_packet, 2, data, length, TIME_MS2I(timeout));
      |                                                                                            ^~~~~~~~~~~~~~~~
      |                                                                                            |
      |                                                                                            uint8_t (*)[2] {aka unsigned char (*)[2]}
In file included from ./lib/chibios/os/hal/include/hal.h:146,
                 from tmk_core/common/chibios/platform_deps.h:18,
                 from quantum/quantum.h:18,
                 from platforms/chibios/drivers/i2c_master.c:27:
./lib/chibios/os/hal/include/hal_i2c.h:146:49: note: expected 'const uint8_t *' {aka 'const unsigned char *'} but argument is of type 'uint8_t (*)[2]' {aka 'unsigned char (*)[2]'}
  146 |                                  const uint8_t *txbuf, size_t txbytes,
      |                                  ~~~~~~~~~~~~~~~^~~~~
cc1: all warnings being treated as errors
 [ERRORS]
 | 

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).