fix typo/thinko in get_random_bytes()

fix typo/thinko in get_random_bytes()

If there is an architecture-specific random number generator we use it
to acquire randomness one "long" at a time.  We should put these random
words into consecutive words in the result buffer - not just overwrite
the first word again and again.

Signed-off-by: Tony Luck <[email protected]>
Acked-by: H. Peter Anvin <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>