arm: apple: Change SoC name from "m1" into "apple"

U-Boot is expected to support multiple generations of Apple SoCs
in a single binary with a single defconfig. Therefore it makes
more sense to set SYS_SOC to "apple".

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-apple/Kconfig b/arch/arm/mach-apple/Kconfig
index 80e8eb2..75ee21e0 100644
--- a/arch/arm/mach-apple/Kconfig
+++ b/arch/arm/mach-apple/Kconfig
@@ -7,7 +7,7 @@
 	default "apple"
 
 config SYS_SOC
-	default "m1"
+	default "apple"
 
 config SYS_MALLOC_LEN
 	default 0x4000000