Fix memory leak in posix_clock_open()

Fix memory leak in posix_clock_open()

[ Upstream commit 5b4cdd9c5676559b8a7c944ac5269b914b8c0bb8 ]

If the clk ops.open() function returns an error, we don't release the
pccontext we allocated for this clock.

Re-organize the code slightly to make it all more obvious.

Reported-by: Rohit Keshri <rkeshri@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Fixes: 60c6946675fc ("posix-clock: introduce posix_clock_context concept")
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linuxfoundation.org>
Stable-dep-of: e859d375d169 ("posix-clock: Store file pointer in struct posix_clock_context")
Signed-off-by: Sasha Levin <sashal@kernel.org>