android/client: Fix incorrect usage of bt_state_t2str()

Fixes clang error:

android/client/if-bt.c:313:54: error: implicit conversion from
enumeration type 'bt_status_t' to different enumeration type
'bt_state_t' [-Werror,-Wenum-conversion]
android/client: Remove duplicate "const" specifier

Fixes clang errors like:

android/client/if-hh.c:181:39: error: duplicate 'const' declaration
specifier [-Werror,-Wduplicate-decl-specifier]