staging: most: hdm-dim2: Remove possible dereference error

Commit 3eced21a ("staging: most: hdm-dim2: Replace request_irq
with devm_request_irq") introduced the following static checker
warning:

drivers/staging/most/hdm-dim2/dim2_hdm.c:841 dim2_probe() error: 'dev->netinfo_task' dereferencing possible ERR_PTR()

Remove the bug introduced by the commit due to change in control flow
by returning PTR_ERR immediately rather than returning at the end of
the function since we do not need to free anything.

Fixes: 3eced21a
Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>