[otbn] Update comment to describe generic functionality

This fixes the wording of a comment to show that the function it
documents works for any OTBN application, not just RSA.

Signed-off-by: Jade Philipoom <jadep@google.com>
diff --git a/sw/device/lib/runtime/otbn.h b/sw/device/lib/runtime/otbn.h
index 6d3551b..c349cf2 100644
--- a/sw/device/lib/runtime/otbn.h
+++ b/sw/device/lib/runtime/otbn.h
@@ -168,7 +168,7 @@
 otbn_result_t otbn_init(otbn_t *ctx, mmio_region_t base_addr);
 
 /**
- * (Re-)loads the RSA application into OTBN.
+ * (Re-)loads the application into OTBN.
  *
  * Load the application image with both instruction and data segments into OTBN.
  *