staging: fbtft: convert a macro to a function.

Convert a macro to an inline function to improve type safety and make
the code simpler.
Signed-off-by: Bhagyashri Dighole <digholebhagyashri@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fb_watterott.c

@@ -90,9 +90,10 @@ static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 	return 0;
 }
 
-#define RGB565toRGB332(c) ((((c) & 0xE000) >> 8) |\
-			   (((c) & 000700) >> 6) |\
-			   (((c) & 0x0018) >> 3))
+static inline int rgb565_to_rgb332(u16 c)
+{
+	return ((c & 0xE000) >> 8) | ((c & 000700) >> 6) | ((c & 0x0018) >> 3);
+}
 
 static int write_vmem_8bit(struct fbtft_par *par, size_t offset, size_t len)
 {
@@ -116,7 +117,7 @@ static int write_vmem_8bit(struct fbtft_par *par, size_t offset, size_t len)
 	for (i = start_line; i <= end_line; i++) {
 		pos[1] = cpu_to_be16(i);
 		for (j = 0; j < par->info->var.xres; j++) {
-			buf8[j] = RGB565toRGB332(*vmem16);
+			buf8[j] = rgb565_to_rgb332(*vmem16);
 			vmem16++;
 		}
 		ret = par->fbtftops.write(par,