bluetooth: Add check for CONFIG_CNSS_PCI

cnss_get_platform_cap() is only defined for CNSS PCI in
cnss driver, hence modify condition to resolve compilation
issue for non PCI based products.

Change-Id: I5443e4a86d75ae4ed8a7238403c70b0cf913fb1b
CRs-Fixed: 2525211
Signed-off-by: Qian Zhang <zhangq@codeaurora.org>