irqchip/qcom-pdc: Split __pdc_enable_intr() into per-version helpers

irqchip/qcom-pdc: Split __pdc_enable_intr() into per-version helpers

The __pdc_enable_intr() function contains a version branch that selects
between two distinct enable mechanisms: a bank-based IRQ_ENABLE_BANK
register for HW < 3.2, and a per-pin enable bit in IRQ_i_CFG for
HW >= 3.2. These two paths share no code and serve different hardware.

Split them into two focused static functions: pdc_enable_intr_bank()
for HW < 3.2 and pdc_enable_intr_cfg() for HW >= 3.2. No functional
change.

Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://patch.msgid.link/20260527095426.2324504-2-mukesh.ojha@oss.qualcomm.com