HID: bpf: move the BIT() macro to hid_bpf_helpers.h

This macro can be useful in mopre than one place

Link: https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/commit/7970a9c17aa0756bad63e89fccb6ee4f2ec83ccc
Signed-off-by: José Expósito <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Benjamin Tissoires <[e-mail]>

drivers/hid/bpf/progs/XPPen__Artist24.bpf.c

···
 	0xc0,                          // End Collection                      106
 };
 
-#define BIT(n) (1UL << n)
-
 #define TIP_SWITCH		BIT(0)
 #define BARREL_SWITCH		BIT(1)
 #define ERASER			BIT(2)

drivers/hid/bpf/progs/hid_bpf_helpers.h

···
 #define HID_VID_ANY				0x0000
 #define HID_PID_ANY				0x0000
 
+#define BIT(n) (1UL << (n))
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
 /* Helper macro to convert (foo, __LINE__)  into foo134 so we can use __LINE__ for