ixgbe: Fix typos and clarify comments in X550 driver code

Corrected spelling errors such as "simular" -> "similar",
"excepted" -> "accepted", and "Determime" -> "Determine".
Fixed including incorrect word usage ("to MAC" -> "two MAC")
and improved awkward phrasing.

Aligned function header descriptions with their actual functionality
(e.g., "Writes a value" -> "Reads a value").
Corrected typo in error code from -ENIVAL to -EINVAL.
Improved overall clarity and consistency in comment across various
functions.

These changes improve maintainability and readability of the code
without affecting functionality.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>