brcmsmac: phytbl_lcn: Remove unused array 'dot11lcn_gain_tbl_rev1'

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

 drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phytbl_lcn.c:108:18: warning: unused variable 'dot11lcn_gain_tbl_rev1' [-Wunused-const-variable]
 static const u32 dot11lcn_gain_tbl_rev1[] = {

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200910065431.657636-29-lee.jones@linaro.org