net: ipa: declare struct types in "ipa_gsi.h"

Pointers to two struct types are used in "ipa_gsi.h", without those
struct types being forward-declared.  Add these declarations.

Fixes: c3f398b1 ("soc: qcom: ipa: IPA interface to GSI")
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_gsi.h

@@ -8,7 +8,9 @@
 
 #include <linux/types.h>
 
+struct gsi;
 struct gsi_trans;
+struct ipa_gsi_endpoint_data;
 
 /**
  * ipa_gsi_trans_complete() - GSI transaction completion callback