ALSA: emu10k1: optimize mask calculation in snd_emu10k1_ptr_read()

Unlike in snd_emu10k1_ptr_write(), we don't need to keep the value's
bits in place, so we can save one shift.
Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230514170323.3408798-4-oswald.buddenhagen@gmx.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/emu10k1/io.c

@@ -50,9 +50,9 @@ unsigned int snd_emu10k1_ptr_read(struct snd_emu10k1 * emu, unsigned int reg, un
 		
 		size = (reg >> 24) & 0x3f;
 		offset = (reg >> 16) & 0x1f;
-		mask = ((1 << size) - 1) << offset;
+		mask = (1 << size) - 1;
 		
-		return (val & mask) >> offset;
+		return (val >> offset) & mask;
 	} else {
 		return val;
 	}