r6040: fix bad usage of udelay

This patch fixes the bad usage of udelay(5000), which in turns is a
mdelay(5). It causes compilation for ARM where udelay maximum value
is checked.

Reported-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Florian Fainelli <florian.fainelli@telecomint.eu>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>