Fix freeing reusable host periodic transfer buffer

[leejugy]

Description

Fixes #6.

_ux_hcd_stm32_periodic_schedule() marks
ux_stm32_ed_data as UX_HCD_STM32_ED_STATUS_ALIGNED_BUFFER_PENDING_FREE
whenever the pointer is non-NULL.

For periodic transfers, ux_stm32_ed_data may point directly to
ux_transfer_request_data_pointer, which is the original reusable
transfer buffer and must not be treated as an HCD-owned aligned buffer.

This change sets PENDING_FREE only when ux_stm32_ed_data differs
from the original transfer request data pointer.

Test

Tested with:

• STM32H563ZIT6
• USBX 6.4.0
• STM32CubeH5 1.7.0
• GL850 USB hub
• MSC device connected downstream of the hub

Before the change, repeated HUB Interrupt IN transactions caused the
reusable transfer buffer to be freed and eventually resulted in
UX_MEMORY_CORRUPTED.

After the change, the reusable HUB interrupt buffer remains valid and
the downstream MSC device operates normally.

[MKISTM]

ST Internal Reference: 42c389938372c714c09687402fda1ed4