[media] s5p-jpeg: avoid overwriting JPEG_CNTL register settings

Take into account the JPEG_CNTL register value read before
setting SYS_INT_EN bit field.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c b/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
index 2de81c7..d9ce40f 100644
--- a/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
+++ b/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
@@ -193,9 +193,9 @@
 	reg = readl(base + EXYNOS4_JPEG_CNTL_REG) & ~(EXYNOS4_SYS_INT_EN);
 
 	if (value == 1)
-		writel(EXYNOS4_SYS_INT_EN, base + EXYNOS4_JPEG_CNTL_REG);
+		writel(reg | EXYNOS4_SYS_INT_EN, base + EXYNOS4_JPEG_CNTL_REG);
 	else
-		writel(~EXYNOS4_SYS_INT_EN, base + EXYNOS4_JPEG_CNTL_REG);
+		writel(reg & ~EXYNOS4_SYS_INT_EN, base + EXYNOS4_JPEG_CNTL_REG);
 }
 
 void exynos4_jpeg_set_stream_buf_address(void __iomem *base,