Makefile: allow to build tags and cscope

It is handy to have cscope and tags built from the sources to
account for any change in source without having to run special
scripts
So, add option to 'make tags' and 'make cscope' to generate
the references.

While at it, ignore these generated files from git tracking.

Signed-off-by: Jin Zheng <j-zheng@ti.com>
cpuinfo: OMAP5: fix cpu device type detection

OMAP5 ES2.0 has a different register compared to OMAP4 for
CONTROL_STATUS.

In addition, the bit range used to store the type of the device has also
been changed w.r.t OMAP4.

Current code reads from the wrong CONTROL register and wrong bits, as a
result of which CPU type is wrongly displayed. Update the code for the
same.

Signed-off-by: Jin Zheng <j-zheng@ti.com>
Merge branch 'cpu_detect_device_type_revision'