usb: misc: nb7vpq904m: remove register read operation

each register contain one parameter,
there is no need to read register before write,
it can improve time when change a mode.

Change-Id: Ifc9e7fd1f9bf9c6a048308dcc0cc2a476d1fc2d4
Signed-off-by: Linyu Yuan <linyyuan@codeaurora.org>