[MTD] [NAND] fix nandsim sched.h references

Fix sched.h references:

build-r7149.out:/local/linsrc/linux-next-20081215/drivers/mtd/nand/nandsim.c:1326: error: dereferencing pointer to incomplete type
build-r7149.out:/local/linsrc/linux-next-20081215/drivers/mtd/nand/nandsim.c:1326: error: 'PF_MEMALLOC' undeclared (first use in this function)
build-r7149.out:/local/linsrc/linux-next-20081215/drivers/mtd/nand/nandsim.c:1328: error: dereferencing pointer to incomplete type
build-r7149.out:/local/linsrc/linux-next-20081215/drivers/mtd/nand/nandsim.c:1335: error: dereferencing pointer to incomplete type
build-r7149.out:/local/linsrc/linux-next-20081215/drivers/mtd/nand/nandsim.c:1335: error: 'PF_MEMALLOC' undeclared (first use in this function)
build-r7149.out:make[4]: *** [drivers/mtd/nand/nandsim.o] Error 1

Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

drivers/mtd/nand/nandsim.c

···
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/random.h>
+#include <linux/sched.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>