msm: kgsl: Fix enum indexing in the adreno CP parser

enum adreno_cp_addr_regs defines a dummy entry (ADRENO_CP_ADDR_MAX)
to specify the maximum allowable address.  Most notably the value
is used to initalize an array of register addresses. Several functions
incorrectly allowed ADRENO_CP_ADDR_MAX to be used as index which
would overstep the bounds of the array.

Change-Id: Ic0dedbadd993c93aef7c80e0621ea022738e772a
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>