mmc: sdhci-msm: Change poor style writel/readl of registers

This patch changes the poor style of writel/readl registers
into more readable format. This avoid mixed style format
of readl/writel in sdhci-msm driver.
This patch also removes the one line comments which were present for
above writel/readl, since they were of no help.

Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>