bsr: add missing MODULE_DESCRIPTION() macro

With ARCH=powerpc, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/bsr.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240615-md-powerpc-drivers-char-v1-1-bff22fd778a4@quicinc.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/bsr.c

@@ -342,5 +342,6 @@ static void __exit  bsr_exit(void)
 
 module_init(bsr_init);
 module_exit(bsr_exit);
+MODULE_DESCRIPTION("IBM POWER Barrier Synchronization Register Driver");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sonny Rao <sonnyrao@us.ibm.com>");