src/poky:bitbake: fetch2/wget: use long arguments for clarity

It's best practise to use long-form arguments in scripts where the
conciseness of short arguments is less useful than in an interactive
terminal.

(Bitbake rev: 54039bc9d169871af6d36578df4c21bff296f6de)

Signed-off-by: Ross Burton <ross.burtonarm.com>
Signed-off-by: Richard Purdie <richard.purdielinuxfoundation.org>

Author: rossburton