All of the hcrypto source files were updated with commit
0f97855826 to include roken.h. This
means that hash.h no longer needs to include the roken header.
Remove the multiple inclusion.
Don't explicitly include system headers in hash.h. These get pulled
in anyway through roken.h, and explicitly including them here makes
compiling hcrypto in the kernel much harder.
Signed-off-by: Love Hornquist Astrand <lha@h5l.org>
