msm: clock-a7: fix memory corruption due to out of boundary write

Out of bounds memory write is seen while reading the "qcom,speed-bin"
property from DTSI. Correct the memory allocation size to fix this
issue.

CRs-Fixed: 594553
Change-Id: Ica250132e9139b874102a7d6c388a76517dea6c3
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>