powerpc: P1020UTM: Separate from P1_P2_RDB_P2 in Kconfig

Use TARGET_P1020UTM instead of sharing with TARGET_P1_P2_RDB_PC
to simplify Kconfig and config macros.

Remove macro CONFIG_P1020UTM.

Signed-off-by: York Sun <york.sun@nxp.com>
9 files changed