usb: host: ehci.h: remove space before open square bracket

Get rid of space before open square bracket.

Caught by checkpatch: "ERROR: space prohibited before open square
bracket '['"

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>