audio/ossaudio: Fix compiler warning with -Wshadow

audio/ossaudio: Fix compiler warning with -Wshadow

The "err" variable is only used twice in this code, in a very
local fashion of first assigning it and then checking it in the
next line. So there is no need to declare this variable a second
time in the innermost block, we can re-use the variable that is
declared at the beginning of the function. This fixes the compiler
warning that occurs with "-Wshadow".

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20231004083900.95856-1-thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>