staging: vt6656: desc.h Remove typedef struct tagSRTS_* to new strutures in rxtx.h

The new structures being
typedef struct tagSRTS_g -> struct vnt_rts_g
typedef struct tagSRTS_g_FB -> struct vnt_rts_g_fb
typedef struct tagSRTS_ab -> struct vnt_rts_ab
typedef struct tagSRTS_a_FB -> struct vnt_rts_a_fb

These are only needed by rxtc.c so moved to rxtx.h and
will eventually form part of the structure of
struct vnt_tx_buffer.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>