USB: Kconfig: Add USB_MSC_PROFILING macro

Add the config USB_MSC_PROFILING in Kconfig as it was missed due to
merge conflicts.

The USB_MSC_PROFILING adds support for populating the read/write
performance values for debugging the Mass storage performance numbers
at VFS level.

Change-Id: I153e2087081e218dc10fb13047d8aa98d9c2e80e
Signed-off-by: Rajkumar Raghupathy <raghup@codeaurora.org>