Input: rmi4 - use local presence map in rmi_read_register_desc()

Input: rmi4 - use local presence map in rmi_read_register_desc()

The presence map is only used during the parsing of the register
descriptor, so we can make it a local variable instead of storing it
in struct rmi_register_descriptor.

Also fix the spelling of the constant and the variable name (presence
instead of presense).

Assisted-by: Gemini:gemini-3.1-pro
Link: https://patch.msgid.link/20260505045952.1570713-9-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>