davinci: make it easier to identify SoC init failures

This patch makes it easier to identify SoC init failures
by panicing when SoC init fails. Without successful SoC
init, the kernel eventually fails when attempt is made to
access the clocks.

Also, an error is printed when JTAG ID match fails to make
it easier to identify failures due to SoC rev changes.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>