USB: gadget: f_fs: remove likely/unlikely

They are used way too often in this file, in some ways that are actually
wrong.  Almost all of these are already known by the compiler and CPU so
just remove them all as none of these should be on any "hot paths" where
it actually matters.

Cc: Felipe Balbi <balbi@kernel.org>
Reported-by: Peter Chen <peter.chen@nxp.com>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20201127140559.381351-6-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>