Remove references to kernel macros.

The macros __force, __bitwise, __user are related to a kernel tool called
sparse to find kernel bugs. These macros are always defined as nothing
in the current uapi kernel header files, so these don't need to be here.

Change-Id: If2b36c2a36f2fce7025302e4b0bf19b6c070ab0b
Test: Builds without warningers/errors.