drivers: CCI: fix the error handle in cci_pmu_probe()

This patch fix the error handle of function cci_pmu_probe():
- using IS_ERR() instead of NULL test for the return value of
  devm_ioremap_resource() since it nerver return NULL.
- remove kfree() for devm_kzalloc allocated memory
- remove dev_warn() since devm_ioremap_resource() has error message
  already.

Change-Id: I8a2536a72d8a070b6637efef6d0112c52c626235
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: fee4f2c66a3b0f0e97e16b3084e8c4151ae9196f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Neil Leeder <nleeder@codeaurora.org>