staging: greybus: arche-platform: declare struct of_device_id as const

Declare the arrays 'arche_platform_of_match' and 'arche_combined_id' as const.

'arche_platform_of_match' is only stored in the .of_match_table field of a
device_driver structure, which is declared as const.

'arche_combined_id' is passed to MODULE_DEVICE_TABLE. This macro does not
modify the array and therefore the array can be declared as const. Checkpatch
pointed out both issues.

WARNING: struct of_device_id should be normally const

Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>