auxdisplay: img-ascii-lcd: fix typo on select SYSCON/MFD_SYSCON

img-ascii-lcd select un-existing SYSCON kconfig name.
This patch fix this error by using the correct MFD_SYSCON kconfig name.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

drivers/auxdisplay/Kconfig

@@ -138,7 +138,7 @@ config IMG_ASCII_LCD
 	tristate "Imagination Technologies ASCII LCD Display"
 	depends on HAS_IOMEM
 	default y if MIPS_MALTA
-	select SYSCON
+	select MFD_SYSCON
 	help
 	  Enable this to support the simple ASCII LCD displays found on
 	  development boards such as the MIPS Boston, MIPS Malta & MIPS SEAD3