net: wwan: t7xx: Fix Runtime PM initialization

net: wwan: t7xx: Fix Runtime PM initialization

For PCI devices the Runtime PM refcount is incremented twice:
1. During device enumeration with a call to pm_runtime_forbid.
2. Just before a driver probe logic is called.
Because of that in order to enable Runtime PM on a given device
we have to call both pm_runtime_allow and pm_runtime_put_noidle,
once it's ready to be runtime suspended.
The former was missing causing the pm refcount to never reach 0.

Fixes: d10b3a695ba0 ("net: wwan: t7xx: Runtime PM")
Signed-off-by: Kornel Dulęba <mindal@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>