target/arm: Don't clear supported PMU events when initializing PMCEID1

target/arm: Don't clear supported PMU events when initializing PMCEID1

A bug was introduced during a respin of:

	commit 57a4a11b2b281bb548b419ca81bfafb214e4c77a
	target/arm: Add array for supported PMU events, generate PMCEID[01]_EL0

This patch introduced two calls to get_pmceid() during CPU
initialization - one each for PMCEID0 and PMCEID1. In addition to
building the register values, get_pmceid() clears an internal array
mapping event numbers to their implementations (supported_event_map)
before rebuilding it. This is an optimization since much of the logic is
shared. However, since it was called twice, the contents of
supported_event_map reflect only the events in PMCEID1 (the second call
to get_pmceid()).

Fix this bug by moving the initialization of PMCEID0 and PMCEID1 back
into a single function call, and name it more appropriately since it is
doing more than simply generating the contents of the PMCEID[01]
registers.

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190123195814.29253-1-aaron@os.amperecomputing.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>