phy: Rename phy-brcmstb-sata driver to phy-brcm-sata driver

Currently, we have a common SATA3 PHY driver for all Broadcom
STB SoCs. This driver can be extended and re-used for Broadcom
iProc SoCs having same SATA3 PHY.

This patch renames existing Broadcom STB SATA3 PHY driver to
common Broadcom SATA3 PHY driver to share this PHY driver across
Broadcom SoCs.

Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>