Input: gscps2 - drop busy-wait and manual interrupt pump on transmit

In gscps2_writeb_output(), after writing data to GSC_XMTDATA, the driver
explicitly executed mdelay(6) and manually called gscps2_interrupt() as a
polling mechanism to accelerate command responses (such as keyboard ACK
or LED updates).

On PA-RISC, the PS/2 controller asserts a level interrupt to the system
ASIC whenever received data arrives in hardware, and the input/serio
subsystem handles command responses asynchronously via completions.
Busy-waiting for 6 ms on every transmitted byte introduces significant
unnecessary latency during multi-byte command sequences and complicates
interrupt handler locking.

Remove mdelay(6) and the manual invocation of gscps2_interrupt() from
gscps2_writeb_output(), relying on normal hardware interrupt delivery.

Reported-by: sashiko-bot@kernel.org
Assisted-by: LLM
Link: https://patch.msgid.link/20260830-gscps2-v1-7-c733d4cae7f9@gmail.com
Acked-by: Helge Deller <deller@gmx.de>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>