usb: host: ehci.h: use space after comma

Put space after comma.

This patch also changes QH_NEXT macro for better reading.

Caught by checkpatch: "ERROR: space required after that ','"

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