board: tbs2910: disable CONFIG_GZIP

As that the resulting image is already very close to the
size limit, and that CONFIG_GZIP is not strictly required,
removing it shouldn't hurt.

With arm-linux-gnueabi-gcc 9.2.0-1 from the Parabola
GNU/Linux distribution we have the following size
reduction:
- text: 9752
- data: 0
- bss: 16
- total: 9768

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
Acked-by: Soeren Moch <smoch@web.de>
diff --git a/configs/tbs2910_defconfig b/configs/tbs2910_defconfig
index 2623eb7..cc459e6 100644
--- a/configs/tbs2910_defconfig
+++ b/configs/tbs2910_defconfig
@@ -88,5 +88,6 @@
 CONFIG_I2C_EDID=y
 CONFIG_VIDEO_IPUV3=y
 CONFIG_VIDEO=y
+# CONFIG_GZIP is not set
 CONFIG_OF_LIBFDT_ASSUME_MASK=0xff
 # CONFIG_EFI_LOADER is not set