MAINTAINERS: fix typo in file name

Commit e31f941c ("MAINTAINERS: update list of qcom drivers") had a
typo in the filename, replace the underscore with dash.

Fixes: e31f941c

 ("MAINTAINERS: update list of qcom drivers")
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <agross@kernel.org>