Fix an alignment issue in iwx(4) Rx descriptors.

Split a 64-bit field, aligned at a 4-byte boundary, into two 32 bit fields.
Our driver does not use this field. Its definition does not matter to us,
as long as its size remains correct.

Fixes clang-15 warnings, which turn into compilation errors with -Werror.

Reported by, and ok tb@

Relevant clang 15 errors are:

In file included from /sys/dev/pci/if_iwx.c:151:
/sys/dev/pci/if_iwxreg.h:3659:2: error: field  within 'struct iwx_rx_mpdu_desc_v1' is less aligned than 'union iwx_rx_mpdu_desc_v1::(anonymous at /sys/dev/pci/if_iwxreg.h:3659:2)' and is usually due to 'struct iwx_rx_mpdu_desc_v1' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
        union {
        ^
/sys/dev/pci/if_iwxreg.h:3626:2: error: field  within 'struct iwx_rx_mpdu_desc_v3' is less aligned than 'union iwx_rx_mpdu_desc_v3::(anonymous at /sys/dev/pci/if_iwxreg.h:3626:2)' and is usually due to 'struct iwx_rx_mpdu_desc_v3' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
        union {
        ^
2 errors generated.

1 files changed, 5 insertions, 3 deletions

diff --git a/sys/dev/pci/if_iwxreg.h b/sys/dev/pci/if_iwxreg.h
index 732c6f18f61..29dc5cbe965 100644
--- a/sys/dev/pci/if_iwxreg.h
+++ b/sys/dev/pci/if_iwxreg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_iwxreg.h,v 1.39 2022/05/10 09:11:44 stsp Exp $	*/
+/*	$OpenBSD: if_iwxreg.h,v 1.40 2023/02/13 15:50:06 stsp Exp $	*/
 
 /*-
  * Based on BSD-licensed source modules in the Linux iwlwifi driver,
@@ -3628,7 +3628,8 @@ struct iwx_rx_mpdu_desc_v3 {
 		 * TSF value on air rise (INA), only valid if
 		 * IWX_RX_MPDU_PHY_TSF_OVERLOAD isn't set
 		 */
-		uint64_t tsf_on_air_rise;
+		uint32_t tsf_on_air_rise0;
+		uint32_t tsf_on_air_rise1;
 
 		struct {
 			uint32_t phy_data0;
@@ -3657,7 +3658,8 @@ struct iwx_rx_mpdu_desc_v1 {
 	uint8_t mac_context;
 	uint32_t gp2_on_air_rise;
 	union {
-		uint64_t tsf_on_air_rise;
+		uint32_t tsf_on_air_rise0;
+		uint32_t tsf_on_air_rise1;
 		struct {
 			uint32_t phy_data0;
 			uint32_t phy_data1;