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>
diff --git a/include/spl.h b/include/spl.h
index 0fedddd..320ed94 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -897,4 +897,14 @@
 
 void board_boot_order(u32 *spl_boot_list);
 void spl_save_restore_data(void);
+
+/*
+ * spl_decompression_enabled() - check decompression support is enabled for SPL build
+ *
+ * Returns  true  if decompression support is enabled, else False
+ */
+static inline bool spl_decompression_enabled(void)
+{
+	return IS_ENABLED(CONFIG_SPL_GZIP);
+}
 #endif