qlnx: gcc build errors

Propagate warning flags from kern.opts.mk and then fix minor -Werror
issues when building with gcc from -Wredundant-decls, -Wnested-externs,
-Wuninitialized.

Reviewed by:	davidcs
Approved by:	markj (mentor)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D11413

sys/dev/qlnx/qlnxe/ecore_hw.h

@@ -89,15 +89,6 @@ enum _dmae_cmd_crc_mask {
 #define DMAE_MIN_WAIT_TIME	0x2
 #define DMAE_MAX_CLIENTS	32
 
-/**
-* @brief ecore_gtt_init - Initialize GTT windows
-*
-* @param p_hwfn
-* @param p_ptt
-*/
-void ecore_gtt_init(struct ecore_hwfn *p_hwfn,
-		    struct ecore_ptt *p_ptt);
-
 /**
  * @brief ecore_ptt_invalidate - Forces all ptt entries to be re-configured
  *

sys/dev/qlnx/qlnxe/qlnx_ioctl.c

@@ -534,12 +534,13 @@ qlnx_get_regs(qlnx_host_t *ha, qlnx_get_regs_t *regs)
 	return (rval);
 }
 
+extern char qlnx_name_str[];
+extern char qlnx_ver_str[];
+
 static int
 qlnx_drv_info(qlnx_host_t *ha, qlnx_drvinfo_t *drv_info)
 {
 	int i;
-	extern char qlnx_name_str[];
-	extern char qlnx_ver_str[];
 
 	bzero(drv_info, sizeof(qlnx_drvinfo_t));
 

sys/dev/qlnx/qlnxe/qlnx_os.c

@@ -396,7 +396,7 @@ qlnx_fp_taskqueue(void *context, int pending)
         qlnx_host_t		*ha;
         struct ifnet		*ifp;
         struct mbuf		*mp;
-        int			ret;
+        int			ret = -1;
 	int			lro_enable;
 	int			rx_int = 0, total_rx_count = 0;
 	struct thread		*cthread;

sys/modules/qlnx/Makefile

@@ -32,6 +32,8 @@
 # $FreeBSD$
 #
 
+SYSDIR?=${SRCTOP}/sys
+.include "${SYSDIR}/conf/kern.opts.mk"
 
 SUBDIR=qlnxe
 

sys/modules/qlnx/qlnxe/Makefile

@@ -50,7 +50,7 @@ SRCS+= device_if.h
 SRCS+= bus_if.h
 SRCS+= pci_if.h
 
-CWARNEXTRA += -Wno-cast-qual
+.include <bsd.kmod.mk>
 
 CFLAGS += -DQLNX_DEBUG
 CFLAGS += -DECORE_PACKAGE
@@ -66,6 +66,4 @@ CFLAGS+= -I${SRCTOP}/sys/compat/linuxkpi/common/include
 #CFLAGS += -DQLNX_QSORT_LRO
 #CFLAGS += -DQLNX_MAX_COALESCE
 
-
-.include <bsd.kmod.mk>
-
+CWARNFLAGS+= -Wno-cast-qual