staging: fbtft: fb_ili9320: Remove unused variable 'ret'

staging: fbtft: fb_ili9320: Remove unused variable 'ret'

Fixes the following W=1 kernel build warning(s):

 drivers/staging/fbtft/fb_ili9320.c: In function ‘read_devicecode’:
 drivers/staging/fbtft/fb_ili9320.c:25:6: warning: variable ‘ret’ set but not used [-Wunused-but-set-variable]

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-staging@lists.linux.dev
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210414181129.1628598-39-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>