wifi: zd1211rw: remove redundant decls

building with W=2 has these errors
redundant redeclaration of ‘zd_rf_generic_patch_6m’ [-Werror=redundant-decls]
redundant redeclaration of ‘zd_rf_patch_6m_band_edge’ [-Werror=redundant-decls]

Remove the second decls.
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230204200902.1709343-1-trix@redhat.com

drivers/net/wireless/zydas/zd1211rw/zd_rf.h

@@ -85,9 +85,6 @@ static inline int zd_rf_should_patch_cck_gain(struct zd_rf *rf)
 	return rf->patch_cck_gain;
 }
 
-int zd_rf_patch_6m_band_edge(struct zd_rf *rf, u8 channel);
-int zd_rf_generic_patch_6m(struct zd_rf *rf, u8 channel);
-
 /* Functions for individual RF chips */
 
 int zd_rf_init_rf2959(struct zd_rf *rf);