staging: skein: threefish_block: Use ror64

Use the inline instead of direct code to improve readability
and shorten the code a little.

Done with perl:

$ perl -p -i -e 's/\((\w+) \>\> (\d+)\) \| \(\1 \<\< \(64 \- \2\)\)/ror64(\1, \2)/g' drivers/staging/skein/threefish_block.c
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>