ALSA: usb-audio: qcom: Use PAGE_ALIGN macro for buffer size calculation

ALSA: usb-audio: qcom: Use PAGE_ALIGN macro for buffer size calculation

Use the kernel's PAGE_ALIGN() macro instead of open-coding the page
alignment calculation. This improves code readability and follows
kernel coding style.

The manual calculation:
  mult = len / PAGE_SIZE;
  remainder = len % PAGE_SIZE;
  len = mult * PAGE_SIZE;
  len += remainder ? PAGE_SIZE : 0;

is equivalent to:
  len = PAGE_ALIGN(len);

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260603091102.231370-4-wangdich9700@163.com