staging: greybus: remove CONFIG_PM_RUNTIME from kernel_ver.h

The last thing remaining in kernel_ver.h was the setting of
CONFIG_PM_RUNTIME, which isn't needed in a in-tree implementation.  So
remove the setting of this value, and the .h file entirely as that was
the last thing left in it.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>