ipw2x00: remove duplicated defines

#define MIN_FRAG_THRESHOLD     256U

#define	MAX_FRAG_THRESHOLD     2346U

/* Frame control field constants */

#define IEEE80211_FCTL_VERS		0x0003

#define IEEE80211_FCTL_FTYPE		0x000c

#define IEEE80211_FCTL_STYPE		0x00f0

#define IEEE80211_FCTL_TODS		0x0100

#define IEEE80211_FCTL_FROMDS		0x0200

#define IEEE80211_FCTL_MOREFRAGS	0x0400

#define IEEE80211_FCTL_RETRY		0x0800

#define IEEE80211_FCTL_PM		0x1000

#define IEEE80211_FCTL_MOREDATA		0x2000

#define IEEE80211_FCTL_PROTECTED	0x4000

#define IEEE80211_FCTL_ORDER		0x8000

#define IEEE80211_FTYPE_MGMT		0x0000

#define IEEE80211_FTYPE_CTL		0x0004

#define IEEE80211_FTYPE_DATA		0x0008

/* management */

#define IEEE80211_STYPE_ASSOC_REQ	0x0000

#define IEEE80211_STYPE_ASSOC_RESP 	0x0010

#define IEEE80211_STYPE_REASSOC_REQ	0x0020

#define IEEE80211_STYPE_REASSOC_RESP	0x0030

#define IEEE80211_STYPE_PROBE_REQ	0x0040

#define IEEE80211_STYPE_PROBE_RESP	0x0050

#define IEEE80211_STYPE_BEACON		0x0080

#define IEEE80211_STYPE_ATIM		0x0090

#define IEEE80211_STYPE_DISASSOC	0x00A0

#define IEEE80211_STYPE_AUTH		0x00B0

#define IEEE80211_STYPE_DEAUTH		0x00C0

#define IEEE80211_STYPE_ACTION		0x00D0

/* control */

#define IEEE80211_STYPE_PSPOLL		0x00A0

#define IEEE80211_STYPE_RTS		0x00B0

#define IEEE80211_STYPE_CTS		0x00C0

#define IEEE80211_STYPE_ACK		0x00D0

#define IEEE80211_STYPE_CFEND		0x00E0

#define IEEE80211_STYPE_CFENDACK	0x00F0

/* data */

#define IEEE80211_STYPE_DATA		0x0000

#define IEEE80211_STYPE_DATA_CFACK	0x0010

#define IEEE80211_STYPE_DATA_CFPOLL	0x0020

#define IEEE80211_STYPE_DATA_CFACKPOLL	0x0030

#define IEEE80211_STYPE_NULLFUNC	0x0040

#define IEEE80211_STYPE_CFACK		0x0050

#define IEEE80211_STYPE_CFPOLL		0x0060

#define IEEE80211_STYPE_CFACKPOLL	0x0070

#define IEEE80211_STYPE_QOS_DATA        0x0080

#define IEEE80211_SCTL_FRAG		0x000F

#define IEEE80211_SCTL_SEQ		0xFFF0

/* QOS control */

#define IEEE80211_QCTL_TID		0x000F