dmaengine: qcom: gpi: Drop unused gpi_write_reg_field()

Static function gpi_write_reg_field() is not used, W=1 build:

gpi.c:573:20: error: unused function 'gpi_write_reg_field' [-Werror,-Wunused-function]

Fixes: 5d0c3533a19f ("dmaengine: qcom: Add GPI dma driver")
Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/qcom/gpi.c

···
 	writel_relaxed(val, addr);
 }
 
-/* gpi_write_reg_field - write to specific bit field */
-static inline void gpi_write_reg_field(struct gpii *gpii, void __iomem *addr,
-				       u32 mask, u32 shift, u32 val)
-{
-	u32 tmp = gpi_read_reg(gpii, addr);
-
-	tmp &= ~mask;
-	val = tmp | ((val << shift) & mask);
-	gpi_write_reg(gpii, addr, val);
-}
-
 static __always_inline void
 gpi_update_reg(struct gpii *gpii, u32 offset, u32 mask, u32 val)
 {