qcacld-3.0: Add one flag to support Genoa IPA over GSI

Add flag IPA_WDI2_GSI to the Kbuild that can be used to
configure whether need to get "is_over_gsi" from IPA driver
for Genoa IPA over GSI case.

Change-Id: Ib6de50d5b3ffb581d85deff089ae77a1a39998ca

Kbuild

@@ -2620,6 +2620,7 @@ cppflags-$(CONFIG_CHECKSUM_OFFLOAD) += -DCHECKSUM_OFFLOAD
 cppflags-$(CONFIG_IPA_OFFLOAD) += -DIPA_OFFLOAD
 
 cppflags-$(CONFIG_WDI3_IPA_OVER_GSI) += -DIPA_WDI3_GSI
+cppflags-$(CONFIG_WDI2_IPA_OVER_GSI) += -DIPA_WDI2_GSI
 
 ifeq ($(CONFIG_ARCH_SDX20), y)
 cppflags-y += -DSYNC_IPA_READY