usb: phy: remove redundant store to variable var after & operation

usb: phy: remove redundant store to variable var after & operation

There is no need to store the result of the & operation back to the
variable var. The store is redundant, replace &= with just &.

Cleans up clang scan warning:
drivers/usb/phy/phy-keystone.c:62:5: warning: Although the value stored to
'val' is used in the enclosing expression, the value is never actually read
from 'val' [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220715225657.353828-1-colin.i.king@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>