clk: msm: clock-alpha-pll: Fix out of bound access

BUG: KASAN: global-out-of-bounds in dyna_alpha_pll_enable+0x1a8/0x450 at
addr ffffffc003412ee0
Read of size 8 by task surfaceflinger/548
page:ffffffba45a3cc60 count:1 mapcount:0 mapping:      (null) index:0x0
flags: 0x400(reserved)
page dumped because: kasan: bad access detected
Address belongs to variable p_vco_8937+0x20/0x40
Call trace:
Memory state around the buggy address:
ffffffc003412d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffc003412e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffc003412e80: 00 00 00 00 fa fa fa fa 00 00 00 fa fa fa fa fa
                                                          ^
ffffffc003412f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffc003412f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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When slewing is enabled the expectation is the vco will operate in the same
vco mode. The calibrated frequency should use only index '0'.

Change-Id: I1fdcb7d8c09b4f7ff41a1c1a9b36351a6c808c47
Signed-off-by: Taniya Das <tdas@codeaurora.org>