leon,grspw_pkt: remove incorrect comment on SMP not being tested

To clarify, SMP with GRSWP_PKT driver API has been extended to
take advantage of multi-core, is now SMP-safe, and has been tested
on GR740.

bsps/sparc/shared/spw/grspw_pkt.c

@@ -2,7 +2,7 @@
  * Cobham Gaisler GRSPW/GRSPW2 SpaceWire Kernel Library Interface for RTEMS.
  *
  * This driver can be used to implement a standard I/O system "char"-driver
- * or used directly. NOTE SMP support has not been tested.
+ * or used directly.
  *
  * COPYRIGHT (c) 2011
  * Cobham Gaisler AB