bus: omap_l3_noc: Add support for discountinous flag mux input numbers

On DRA7, unlike on OMAP4 and OMAP5, the flag mux input numbers used
to indicate the source of errors are not continous. Have a way in the
driver to catch these and WARN the user of the flag mux input thats
either undocumented or wrong.

In the similar vein, Timeout errors in AM43x can't be cleared per h/w
team, neither does it have a STDERRLOG_MAIN to clear the error.

Further, the mux bit offset might not even be indexed into our array
of known mux input description, in which case we'd have a abort.

So, define a static range check for bit description and any definition
which has target_name set to NULL (the ones that are not populated or
ones that are specifically marked in the case of discontinous input
numbers), can handle the same gracefully. Upon occurance of error from
such sources, mask it. Otherwise, we'd have an infinite interrupt
source without any means to clear it.

NOTE: follow on patch ensures that these masked bits are ignored.

[nm@ti.com: rebase, squash and improve]
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Darren Etheridge <detheridge@ti.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>