IB/srp: Avoid problems if a header uses pr_fmt

SRP defines pr_fmt(fmt) to be "PFX fmt", and then includes a bunch of
header files before it gets around to defining PFX.  This causes
problems if any of the header files do a pr_... and use pr_fmt().

Fix this by using KBUILD_MODNAME instead of the private PFX.
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/ulp/srp/ib_srp.c

@@ -30,7 +30,7 @@
  * SOFTWARE.
  */
 
-#define pr_fmt(fmt) PFX fmt
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/module.h>
 #include <linux/init.h>