coresight: tpiu: Fix disabling timeouts

Probing the TPIU driver under UBSan triggers an out-of-bounds shift
warning in coresight_timeout():

...
[    5.677530] UBSAN: Undefined behaviour in drivers/hwtracing/coresight/coresight.c:929:16
[    5.685542] shift exponent 64 is too large for 64-bit type 'long unsigned int'
...

On closer inspection things are exponentially out of whack because we're
passing a bitmask where a bit number should be. Amusingly, it seems that
both calls will find their expected values by sheer luck and appear to
succeed: 1 << FFCR_FON_MAN ends up at bit 64 which whilst undefined
evaluates as zero in practice, while 1 << FFSR_FT_STOPPED finds bit 2
(TCPresent) which apparently is usually tied high.

Following the examples of other drivers, define separate FOO and FOO_BIT
macros for masks vs. indices, and put things right.

CC: Robert Walker <robert.walker@arm.com>
CC: Mike Leach <mike.leach@linaro.org>
CC: Mathieu Poirier <mathieu.poirier@linaro.org>
Fixes: 11595db8

 ("coresight: Fix disabling of CoreSight TPIU")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>