brcmfmac: remove watchdog reset from brcmf_pcie_buscoreprep()

The watchdog reset as done in brcmf_pcie_buscoreprep() is not
sufficient. It needs to modify PCIe core registers as well
which is properly done by brcmf_pcie_reset_device() after the
chip recognition is done. So the faulty watchdog reset can be
removed as it was causing driver reload to fail and hang the
system requiring a power-cycle. Instead the call to to the
brcmf_pcie_reset_device() function is done twice in the unload.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>