Fix enum warning in ath_hal's ar9002

This fixes a clang 19 warning:

    sys/dev/ath/ath_hal/ar9002/ar9285_btcoex.c:57:32: error: comparison of different enumeration types ('HAL_BOOL' and 'HAL_ANT_SETTING') [-Werror,-Wenum-compare]
       57 |             (AH5212(ah)->ah_diversity != HAL_ANT_VARIABLE)) {
          |              ~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~

The `ah_diversity` field of `struct ath_hal_5212` is of type `HAL_BOOL`,
not the enum type `HAL_ANT_SETTING`. In other code, `ah_diversity` is
set to `AH_TRUE` whenever the related field `ah_antControl` is set to
`HAL_ANT_VARIABLE`.

It is not entirely clear to me what the intended statement is here: the
test as it is written now compares the enum value 0 to `ah_diversity`,
so in effect it enables the following block whenever `ah_diversity` is
`AH_TRUE`. Write it like that, to avoid the compiler warning.

MFC after:	3 days

0 files changed, 0 insertions, 0 deletions