video: fbdev: nvidia: Fix set but not used warnings

Fix warnings by deleting unused code. The register reads are
kept as it is unknown if there are any hidden side-effects.

v2:
  - Update subject (Lee)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: linux-fbdev@vger.kernel.org
Cc: Lee Jones <lee.jones@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201128224114.1033617-21-sam@ravnborg.org

drivers/video/fbdev/nvidia/nv_setup.c

@@ -89,9 +89,8 @@ u8 NVReadSeq(struct nvidia_par *par, u8 index)
 }
 void NVWriteAttr(struct nvidia_par *par, u8 index, u8 value)
 {
-	volatile u8 tmp;
 
-	tmp = VGA_RD08(par->PCIO, par->IOBase + 0x0a);
+	VGA_RD08(par->PCIO, par->IOBase + 0x0a);
 	if (par->paletteEnabled)
 		index &= ~0x20;
 	else
@@ -101,9 +100,7 @@ void NVWriteAttr(struct nvidia_par *par, u8 index, u8 value)
 }
 u8 NVReadAttr(struct nvidia_par *par, u8 index)
 {
-	volatile u8 tmp;
-
-	tmp = VGA_RD08(par->PCIO, par->IOBase + 0x0a);
+	VGA_RD08(par->PCIO, par->IOBase + 0x0a);
 	if (par->paletteEnabled)
 		index &= ~0x20;
 	else