wkup_m3_ipc.c: Fix error checking for debugfs_create_dir

This patch fixes the error checking in wkup_m3_ipc.c in
debugfs_create_dir. The correct way to check if an error occurred
is 'IS_ERR' inline function.

Signed-off-by: Osama Muhammad <osmtendev@gmail.com>
Link: https://lore.kernel.org/r/20230517172431.13507-1-osmtendev@gmail.com


Signed-off-by: Nishanth Menon <nm@ti.com>