hwrng: Kconfig - Move one "tristate" Kconfig description to the usual place

It's pretty usual to have "tristate" descriptions in Kconfig files placed
immediately after the actual configuration options, so correct the position
of one misplaced "tristate" spotted in the hw_random Kconfig file.

No intended functional changes are introduced by this trivial cleanup.

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>