carl9170: Convert 'ar9170_qmap' to inline function

'ar9170_qmap' is used in some source files which include carl9170.h,
but not all of them.  A 'defined but not used' warning is thrown when
compiling the ones which do not use it.

Fixes the following W=1 kernel build warning(s)

 from drivers/net/wireless/ath/carl9170/carl9170.h:57,
 In file included from drivers/net/wireless/ath/carl9170/carl9170.h:57,
 drivers/net/wireless/ath/carl9170/carl9170.h:71:17: warning: ‘ar9170_qmap’ defined but not used [-Wunused-const-variable=]

 NB: Snipped - lots of these repeat

Cc: Christian Lamparter <chunkeey@googlemail.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200827093351.GA1627017@dell