spu_create.2: Clarify that spu_create() now has 4 arguments but once had only 3

Reported-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/spu_create.2

@@ -30,7 +30,6 @@ spu_create \- create a new spu context
 .B #include <sys/types.h>
 .B #include <sys/spu.h>
 .PP
-.BI "int spu_create(const char *" pathname ", int " flags ", mode_t " mode ");"
 .BI "int spu_create(const char *" pathname ", int " flags ", mode_t " mode ","
 .BI "               int " neighbor_fd ");"
 .fi
@@ -89,6 +88,12 @@ for a full list of the possible
 values.
 .PP
 The
+.I neighbor_fd
+is used only when the
+.B SPU_CREATE_AFFINITY_SPU
+flag is specified; see below.
+.PP
+The
 .I flags
 argument can be zero or any bitwise OR-ed
 combination of the following constants:
@@ -264,6 +269,14 @@ See
 .UR http://www.bsc.es\:/projects\:/deepcomputing\:/linuxoncell/
 .UE
 for the recommended libraries.
+.PP
+Prior to the addition of the
+.B SPU_CREATE_AFFINITY_SPU
+flag in Linux 2.6.23, the
+.BR spu_create ()
+system call took only three arguments (i.e., there was no
+.I neighbor_fd
+argument).
 .SH EXAMPLES
 See
 .BR spu_run (2)