phy: qcom-qmp-usb: statify qmp_phy_vreg_l

qmp_phy_vreg_l should be marked static, this resolves warning:

drivers/phy/qualcomm/phy-qcom-qmp-combo.c:616:27: warning: symbol 'qmp_phy_vreg_l' was not declared. Should it be static?

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220708052059.3049443-1-vkoul@kernel.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>