soc: qcom: socinfo: Use seq_putc() if possible

soc: qcom: socinfo: Use seq_putc() if possible

This is a single character that we're printing out. Use seq_putc() for
that to simplify the code.

Cc: Vaishali Thakkar <vaishali.thakkar@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200309185123.65265-1-swboyd@chromium.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>