meson: Use more portable compiler option -std.

GCC and Clang support --std and -std options but Intel C++ Compiler only supports -std.

icpc: command line warning #10159 (closed): invalid argument for option '--std'

Fixes: 8a05d6ff ("driconf: Make the driver's declarations be structs instead of XML.") Signed-off-by: Vinson Lee vlee@freedesktop.org