mei: amthif: Do not compare bool to 0/1

Spotted by coccicheck:
drivers/misc/mei/amthif.c:479:5-26: WARNING: Comparison of bool to 0/1

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>