spl: fit: support for booting a GZIP-compressed U-boot binary

spl: fit: support for booting a GZIP-compressed U-boot binary

If GZIP Compression support is enabled, GZIP compressed U-Boot binary
will be at a specified RAM location which is defined at
CONFIG_SYS_LOAD_ADDR and will be assign it as the source address.

gunzip function in spl_load_fit_image ,will decompress the GZIP
compressed U-Boot binary which is placed at
source address(CONFIG_SYS_LOAD_ADDR)  to the default
CONFIG_SYS_TEXT_BASE location.

spl_load_fit_image function will load the decompressed U-Boot
binary, which is placed at the CONFIG_SYS_TEXT_BASE location.

Signed-off-by: Manoj Sai <abbaraju.manojsai@amarulasolutions.com>
Signed-off-by: Suniel Mahesh <sunil@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>