iio: mma8452: Fix trigger reference couting

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: iio: mma8452: Fix trigger reference couting The mma8452 driver directly assigns a trigger to the struct iio_dev. The IIO core when done using this trigger will call `iio_trigger_put()` to drop the reference count by 1. Without the matching `iio_trigger_get()` in the driver the reference count can reach 0 too early, the trigger gets freed while still in use and a use-after-free occurs. Fix this by getting a reference to the trigger before assigning it to the IIO device.

References

• https://git.kernel.org/stable/c/094d513b78b1714113bc016684b8142382e071ba
• https://git.kernel.org/stable/c/fb75cc4740d81264cd5bcb0e17d961d018a8be96
• https://git.kernel.org/stable/c/794c0898f6bf39a458655d5fb4af70ec43a5cfcb
• https://git.kernel.org/stable/c/f5deab10ced368c807866283f8b79144c4823be8
• https://git.kernel.org/stable/c/acf0088ac073ca6e7f4cad6acac112177e08df5e
• https://git.kernel.org/stable/c/db12d95085367de8b0223929d1332731024441f1
• https://git.kernel.org/stable/c/c43517071dfc9fce34f8f69dbb98a86017f6b739
• https://git.kernel.org/stable/c/cd0082235783f814241a1c9483fb89e405f4f892