broadcom-wl: hack to work around a bug in the PCIe controller

Thank you nlh

This closes #12930.

SVN-Revision: 35767

package/broadcom-wl/patches/913-avoid-dbe-on-ifs_ctl-readw-hack.patch

+--- a/driver/linux_osl.c
++++ b/driver/linux_osl.c
+@@ -723,6 +723,9 @@ osl_readl(volatile uint32 *r)
+ uint16
+ osl_readw(volatile uint16 *r)
+ {
++	uint32 addr = (uintptr)r & 0xffff3fff;
++	if (addr == 0xa8000688)	/* ifs_ctl */
++		readl(r);
+ 	return (readw(r));
+ }
+