Bluetooth: btbcm: Add entry for BCM4373A0 UART Bluetooth

This patch adds the device ID for the BCM4373A0 module, found e.g. in
the Infineon (Cypress) CYW4373E chip. The required firmware file is
named 'BCM4373A0.hcd'.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>