sunxi: Add default partition scheme

The partitions variable is especially useful to create a partition table
from U-Boot, either directly from the U-Boot shell, or through flashing
tools like fastboot and its oem format command.

This is especially useful on devices with an eMMC you can't take out to
flash from another system, and booting a Linux system first to flash our
system then is not really practical.
Reviewed-by: NAndre Przywara <andre.przywara@arm.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

include/configs/sunxi-common.h

@@ -493,6 +493,20 @@ extern int soft_i2c_gpio_scl;
 #define SUNXI_MTDPARTS_DEFAULT
 #endif
 
+#define PARTS_DEFAULT \
+	"name=loader1,start=8k,size=32k,uuid=${uuid_gpt_loader1};" \
+	"name=loader2,size=984k,uuid=${uuid_gpt_loader2};" \
+	"name=esp,size=128M,bootable,uuid=${uuid_gpt_esp};" \
+	"name=system,size=-,uuid=${uuid_gpt_system};"
+
+#define UUID_GPT_ESP "c12a7328-f81f-11d2-ba4b-00a0c93ec93b"
+
+#ifdef CONFIG_ARM64
+#define UUID_GPT_SYSTEM "b921b045-1df0-41c3-af44-4c6f280d3fae"
+#else
+#define UUID_GPT_SYSTEM "69dad710-2ce4-4e3c-b16c-21a1d49abed3"
+#endif
+
 #define CONSOLE_ENV_SETTINGS \
 	CONSOLE_STDIN_SETTINGS \
 	CONSOLE_STDOUT_SETTINGS
@@ -511,6 +525,9 @@ extern int soft_i2c_gpio_scl;
 	"console=ttyS0,115200\0" \
 	SUNXI_MTDIDS_DEFAULT \
 	SUNXI_MTDPARTS_DEFAULT \
+	"uuid_gpt_esp=" UUID_GPT_ESP "\0" \
+	"uuid_gpt_system=" UUID_GPT_SYSTEM "\0" \
+	"partitions=" PARTS_DEFAULT "\0" \
 	BOOTCMD_SUNXI_COMPAT \
 	BOOTENV