meson-gx-socinfo: Fix package id parsing

I've noticed the following message while booting a S905X based board:

soc soc0: Amlogic Meson GXL (S905D) Revision 21:82 (b:2) Detected

The S905D string is obviously wrong. The vendor code does:
...
        ver = (readl(assist_hw_rev) >> 8) & 0xff;
        meson_cpu_version[MESON_CPU_VERSION_LVL_MINOR] = ver;
        ver =  (readl(assist_hw_rev) >> 16) & 0xff;
        meson_cpu_version[MESON_CPU_VERSION_LVL_PACK] = ver;
...

while the current code does:
...
...

This means that the current mainline code has package id and minor
version reversed.

Fixes: a9daaba2 ("soc: Add Amlogic SoC Information driver")
Signed-off-by: Arnaud Patard <apatard@hupstream.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>