[openal] Same expression on both sides of '&&'

[Carlos Olmedo Escobar]

Hi,

In the line 753 of the file sf2load.c you have an if statement with
the same expression twice (src0type != AL_INVALID). I guess the second
src0type is meant to be src1type. I'm not familiar enough with your
code so please take a look yourself...

Regards.