drivers: qcom: stats: define readq_relaxed for ARM variants

ARM cannot natively read 64-bit address. As such the readq_ variants
are not defined for this architecture. Add a 32-bit equivalent to read 2
sequential 4-byte memory into a u64 value. Let's keep them locally
defined for now, since they are not native to the ARM architecture.

Change-Id: Ib0ce08c3b8a37af85c12c2ad72803bf871847f67
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Tushar Nimkar <tnimkar@codeaurora.org>