Staging: fbtft: fb_ra8875: Remove useless cast

Remove explicit type conversion as it is not required.
Semantic patch used:

@@
type T;
T e;
identifier x;
@@

* T x = (T)e;

Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fb_ra8875.c

@@ -204,7 +204,7 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
 {
 	va_list args;
 	int i, ret;
-	u8 *buf = (u8 *)par->buf;
+	u8 *buf = par->buf;
 
 	/* slow down spi-speed for writing registers */
 	par->fbtftops.write = write_spi;