cxl/Documentation: Fix typo in sysfs write_bandwidth attribute path

Fix a typo in the sysfs documentation for the CXL "write_bandwidth"
attribute path. The attribute was incorrectly documented as write_banwidth.
Update it to the correct write_bandwidth to align with the actual
implementation.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Link: https://patch.msgid.link/20250516103855.3820882-1-alok.a.tiwari@oracle.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Author: aloktiwa

Documentation/ABI/testing/sysfs-bus-cxl

@@ -572,7 +572,7 @@ Description:
 
 
 What:		/sys/bus/cxl/devices/regionZ/accessY/read_bandwidth
-		/sys/bus/cxl/devices/regionZ/accessY/write_banwidth
+		/sys/bus/cxl/devices/regionZ/accessY/write_bandwidth
 Date:		Jan, 2024
 KernelVersion:	v6.9
 Contact:	linux-cxl@vger.kernel.org