[PATCH v3 5/8] staging: r8188eu: use sizeof instead of hardcoded firmware header size

[Michael Straube <straube.linux@gmail.com>]

Use sizeof() instead of hardcoding the firmware header size and add
a compile time check to ensure struct rt_firmware_hdr has the correct
size.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
---
v3:
- added the compile time size check from patch 8/8 of v2

v2:
- no changes

 drivers/staging/r8188eu/core/rtw_fw.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_fw.c b/drivers/staging/r8188eu/core/rtw_fw.c
index 3da52a1ba23c..0279af37719a 100644
--- a/drivers/staging/r8188eu/core/rtw_fw.c
+++ b/drivers/staging/r8188eu/core/rtw_fw.c
@@ -34,6 +34,8 @@ struct rt_firmware_hdr {
 	__le32	rsvd5;
 };
 
+static_assert(sizeof(struct rt_firmware_hdr) == 32);
+
 static void fw_download_enable(struct adapter *padapter, bool enable)
 {
 	u8 tmp;
@@ -263,9 +265,8 @@ int rtl8188e_firmware_download(struct adapter *padapter)
 			DRIVER_PREFIX, fw_version, fw_subversion, fw_signature);
 
 	if (IS_FW_HEADER_EXIST(fwhdr)) {
-		/*  Shift 32 bytes for FW header */
-		fw_data = fw_data + 32;
-		fw_size = fw_size - 32;
+		fw_data = fw_data + sizeof(struct rt_firmware_hdr);
+		fw_size = fw_size - sizeof(struct rt_firmware_hdr);
 	}
 
 	/*  Suggested by Filen. If 8051 is running in RAM code, driver should inform Fw to reset by itself, */
-- 
2.35.1