staging: sm750fb: Remove set but not used variable 'uiActualPixelClk'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/staging/sm750fb/ddk750_mode.c: In function ddk750_setModeTiming:
drivers/staging/sm750fb/ddk750_mode.c:212:15: warning: variable uiActualPixelClk set but not used [-Wunused-but-set-variable]

It is not used since commit 81dee67e ("staging:
sm750fb: add sm750 to staging")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/1570520515-2186-3-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/sm750fb/ddk750_mode.c

@@ -209,12 +209,11 @@ static int programModeRegisters(struct mode_parameter *pModeParam,
 int ddk750_setModeTiming(struct mode_parameter *parm, enum clock_type clock)
 {
 	struct pll_value pll;
-	unsigned int uiActualPixelClk;
 
 	pll.input_freq = DEFAULT_INPUT_CLOCK;
 	pll.clock_type = clock;
 
-	uiActualPixelClk = sm750_calc_pll_value(parm->pixel_clock, &pll);
+	sm750_calc_pll_value(parm->pixel_clock, &pll);
 	if (sm750_get_chip_type() == SM750LE) {
 		/* set graphic mode via IO method */
 		outb_p(0x88, 0x3d4);