Input: stmfts - fix a & vs && typo

In stmfts_sysfs_hover_enable_write(), we should check value and
sdata->hover_enabled is all true.

Fixes: 78bcac7b ("Input: add support for the STMicroelectronics FingerTip touchscreen")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20200916141941.16684-1-yuehaibing@huawei.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>