acpi_check_dsm() and acpi_evaluate_dsm_typed() take a guid_t argument
and not a char *. For in-tree Linux based drivers this leads to a
compile error due to a warning. Fix the function argument type and
cast internally.

While this made the long statements in the wrapper functions for *_dsm_*
even less readale split them up using a local variable.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

Compile-tested with other changes against drm-kmod 6.1-lts, 6.6-lts, master