hw/block/pflash_cfi01: Removed an unused timer

hw/block/pflash_cfi01: Removed an unused timer

The 'CFI02' NOR flash was introduced in commit 29133e9a0fff, with
timing modelled. One year later, the CFI01 model was introduced
(commit 05ee37ebf630) based on the CFI02 model. As noted in the
header, "It does not support timings". 12 years later, we never
had to model the device timings. Time to remove the unused timer,
we can still add it back if required.

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
[Laszlo Ersek: Regression tested EDK2 OVMF IA32X64, ArmVirtQemu Aarch64
https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg04373.html]
Message-Id: <20190716221555.11145-2-philmd@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>