cleanup: Add conditional guard helper

Add a new if_not_guard() macro to cleanup.h for handling
conditional guards such as mutext_trylock().

This is more ergonomic than scoped_guard() for most use cases.
Instead of hiding the error handling statement in the macro args, it
works like a normal if statement and allow the error path to be indented
while the normal code flow path is not indented. And it avoid unwanted
side-effect from hidden for loop in scoped_guard().

Signed-off-by: David Lechner <dlechner@baylibre.com>
Co-developed-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>
Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lkml.kernel.org/r/20241001-cleanup-if_not_cond_guard-v1-1-7753810b0f7a@baylibre.com