macro attributes should be used with brackets

[bitluni]

Low-level macros are vulnerable to operator priorities which can cause problems. Took me some time to find why my code didn't work

Arduino/tools/sdk/include/eagle_soc.h rows:

# define GPIO_REG_READ(reg)                         READ_PERI_REG(PERIPHS_GPIO_BASEADDR + reg)
# define GPIO_REG_WRITE(reg, val)                 WRITE_PERI_REG(PERIPHS_GPIO_BASEADDR + reg, val)

should bechanged to:

# define GPIO_REG_READ(reg)                         READ_PERI_REG(PERIPHS_GPIO_BASEADDR + (reg))
# define GPIO_REG_WRITE(reg, val)                 WRITE_PERI_REG(PERIPHS_GPIO_BASEADDR + (reg), val)

[devyte]

@bitluni I still see this in the latest code. Care to make a PR?