staging: rts_pstor: dont cast void* from kmalloc()

staging: rts_pstor: dont cast void* from kmalloc()

 Casting (void *) value returned by kmalloc is useless
 as mentioned in Documentation/CodingStyle, Chap 14.

 The semantic patch that makes this output is available
 in scripts/coccinelle/api/alloc/drop_kmalloc_cast.cocci.

 More information about semantic patching is available at
 http://coccinelle.lip6.fr/

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>