rockchip: misc: read the correct number of bytes from the efuse

Originally the cpuid var the value gets read into was defined as
    u8 cpuid[RK3399_CPUID_LEN];
hence the sizeof(cpuid) would return the correct the correct number
of array elements.

With the move to a separate function cpuid becomes a pointer and
sizeof(cpuid) hence returns the pointer size - 8 in the arm64 case.

We do have the actual id length available as function param so use
it for actual amount of bytes to read.

Fixes: 04825384999f ("rockchip: rk3399: derive ethaddr from cpuid")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Kever Yang<kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/misc.c b/arch/arm/mach-rockchip/misc.c
index fdb763c..c0e4fdb 100644
--- a/arch/arm/mach-rockchip/misc.c
+++ b/arch/arm/mach-rockchip/misc.c
@@ -70,7 +70,7 @@
 	}
 
 	/* read the cpu_id range from the efuses */
-	ret = misc_read(dev, cpuid_offset, cpuid, sizeof(cpuid));
+	ret = misc_read(dev, cpuid_offset, cpuid, cpuid_length);
 	if (ret) {
 		debug("%s: reading cpuid from the efuses failed\n",
 		      __func__);