wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy()

In 'wlc_phy_iqcal_gainparams_nphy()', add gain range check to WARN()
instead of possible out-of-bounds 'tbl_iqcal_gainparams_nphy' access.
Compile tested only.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20241210070441.836362-1-dmantipov@yandex.ru