vinput: Fix multiple issue

[visitorckw]

Fix multiple issues for vinput module:

1. Removes redundant memset calls that were unnecessary since memory allocated with kzalloc is already zeroed due to the __GFP_ZERO gfp flag.
2. Fixes a NULL pointer dereference caused by failed kzalloc allocation. It adds a check for the return value of kzalloc and handles failed allocations by printing an error message and returning ERR_PTR(-ENOMEM).
3. Corrects the handling of failures in raw_copy_to_user() in vinput_read(). Previously, the function would modify '*offset' incorrectly on raw_copy_to_user() failure. Fix this behavior by changing count = -EFAULT to return -EFAULT instead.

[jserv]

Can you check #52 ?

[linD026]

Looks good to me.

[visitorckw]

Can you check #52 ?

I can spend some time understanding try_module_get and put_module_get and try to resolve this issue.

[jserv]

Thank @visitorckw for contributing!