fix(bhi160): Fix interrupt behavior during initialization

As discussed in issue card10/firmware#133, the BHI160 changes its
interrupt behavior during initialization.  In commit 2f56ff36
("fix(bhi160): Call bhy_mapping_matrix_set twice for the first time")
a quick workaround for this issue was added.  Replace this hack with
a proper fix by reconfiguring the interrupt on the host side according
to the specification.

(Finally) fixes card10/firmware#133.

Fixes: 2f56ff36 ("fix(bhi160): Call bhy_mapping_matrix_set twice for the first time")
Link: https://git.card10.badge.events.ccc.de/card10/firmware/issues/133#note_5894


Signed-off-by: Rahix <rahix@rahix.de>