staging: r8188eu: remove sha256_state structure

This structure does not used in driver code.
Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/include/rtw_security.h

@@ -164,12 +164,6 @@ struct security_priv {
 	u8 bWepDefaultKeyIdxSet;
 };
 
-struct sha256_state {
-	u64 length;
-	u32 state[8], curlen;
-	u8 buf[64];
-};
-
 #define GET_ENCRY_ALGO(psecuritypriv, psta, encry_algo, bmcst)		\
 do {									\
 	switch (psecuritypriv->dot11AuthAlgrthm) {			\