fix off-by-one error for when working with ULP addresses

binutils-esp32ulp allows peripheral registers to be specified
either as a full address (e.g. 0x3ff48000) or as a direct ULP
address (e.g. 0x120), i.e. the address as seen from the ULP.
"direct" addresses are anything from 0x0 to 0x3ff (inclusive).
This change ensures that 0x3ff is included in what is treated
as a direct ULP address.

(See https://github.com/espressif/binutils-esp32ulp/blob/249ec34/gas/config/tc-esp32ulp_esp32.c#L145
for reference to how binutils treats anything larger than
DR_REG_MAX_DIRECT (0x3ff) as a full address, so everything
less *AND* equal to DR_REG_MAX_DIRECT is therefore a direct
ULP address.)

This commit contributes to being able to eventually assemble the
esp32ulp_ranges.s test from binutils-esp32ulp. It addresses this line:
https://github.com/espressif/binutils-esp32ulp/blob/249ec34/gas/testsuite/gas/esp32ulp/esp32/esp32ulp_ranges.s#L136

Author: wnienhaus

esp32_ulp/opcodes.py

@@ -358,7 +358,7 @@ def get_cond(arg):
 
 def _soc_reg_to_ulp_periph_sel(reg):
     # Map SoC peripheral register to periph_sel field of RD_REG and WR_REG instructions.
-    if reg < DR_REG_MAX_DIRECT:
+    if reg <= DR_REG_MAX_DIRECT:
         ret = RD_REG_PERIPH_RTC_CNTL
     elif reg < DR_REG_RTCCNTL_BASE:
         raise ValueError("invalid register base")
@@ -377,7 +377,7 @@ def _soc_reg_to_ulp_periph_sel(reg):
 
 def i_reg_wr(reg, high_bit, low_bit, val):
     reg = get_imm(reg)
-    if reg < DR_REG_MAX_DIRECT:  # see https://github.com/espressif/binutils-esp32ulp/blob/master/gas/config/tc-esp32ulp_esp32.c
+    if reg <= DR_REG_MAX_DIRECT:  # see https://github.com/espressif/binutils-esp32ulp/blob/master/gas/config/tc-esp32ulp_esp32.c
         _wr_reg.addr = reg
     else:
         _wr_reg.addr = (reg & 0xff) >> 2
@@ -391,7 +391,7 @@ def i_reg_wr(reg, high_bit, low_bit, val):
 
 def i_reg_rd(reg, high_bit, low_bit):
     reg = get_imm(reg)
-    if reg < DR_REG_MAX_DIRECT: # see https://github.com/espressif/binutils-esp32ulp/blob/master/gas/config/tc-esp32ulp_esp32.c
+    if reg <= DR_REG_MAX_DIRECT:  # see https://github.com/espressif/binutils-esp32ulp/blob/master/gas/config/tc-esp32ulp_esp32.c
         _rd_reg.addr = reg
     else:
         _rd_reg.addr = (reg & 0xff) >> 2