mei: constify passed buffers and structures

Buffers and structures passed to MEI bus and client API can be made
const for safer code and clear indication that it is not modified.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210729102803.46289-1-krzysztof.kozlowski@canonical.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>